Prototype 2 Dlc Unlocker-3dm Mod Now
Prototype 2 remains a cult classic in the open-world action genre. Released in 2012, it let players step into the shoes of Sgt. James Heller, a man consumed by rage and viral mutation, as he tore through the zombie-infested streets of New York Zero. While the base game offered a brutal 10-12 hour campaign, many players felt the experience was incomplete without the additional content locked behind pre-order bonuses, special edition exclusives, or region-locked DLC.
Enter the Prototype 2 DLC Unlocker-3DM mod. For years, this community-driven patch has been the go-to solution for PC gamers, particularly those who own the base game (or non-complete editions) and want to access every piece of cosmetic and gameplay content without repurchasing the title. But what exactly is this mod, how does it work, and is it worth the risk?
In this deep-dive article, we will explore the history of the 3DM cracking group, the technical function of the unlocker, a step-by-step installation guide, and the legal gray areas you should be aware of.
Would you like help finding legitimate ways to access the Prototype 2 DLC instead?
Prototype 2 DLC Unlocker: A 3DM Mod to Enhance Your Gaming Experience
Prototype 2, developed by Radical Entertainment and published by Activision, is an action-adventure game released in 2012. The game received positive reviews for its engaging storyline, improved gameplay mechanics, and stunning visuals. However, some players felt that certain downloadable content (DLC) packs were locked behind paywalls, limiting their access to additional gameplay features and storylines.
What is the 3DM Mod?
The 3DM modding community has developed a popular mod for Prototype 2, known as the DLC Unlocker. This mod allows players to unlock all the DLC packs, including the "DLC Bundle" and "Extra Costume" packs, without having to purchase them separately. The mod is designed to work seamlessly with the game's existing files, ensuring a smooth and hassle-free gaming experience.
Key Features of the DLC Unlocker Mod
Benefits of Using the DLC Unlocker Mod
How to Install the DLC Unlocker Mod
Important Notes
In conclusion, the Prototype 2 DLC Unlocker mod developed by 3DM offers players a convenient way to access all the game's content without having to purchase individual DLC packs. While the mod may not be for everyone, it provides an attractive option for players looking to enhance their gaming experience and explore all that Prototype 2 has to offer.
The Prototype 2 DLC Unlocker by 3DM is a community-created mod designed to enable the "Colossal Mayhem" and "Excessive Force" DLC packs on the PC version of the game. These packs were originally difficult to access or unpurchasable on certain platforms like Steam but are often present in the game's core files. Key Features & Inclusions
Colossal Mayhem Pack: Typically includes the Thermobaric Launcher weapon and various skins (e.g., Hellenstein, Infected James Heller).
Excessive Force Pack: Adds the Viral Detector power, the Warp Vortex power, and additional skins like Armor Alex Mercer.
RADNET Content: Some versions of the unlocker also attempt to enable RADNET rewards, which include unique mutations and behind-the-scenes content. Installation Method
The 3DM mod generally follows a simple "copy-paste" procedure: Download and Extract: Unzip the mod files.
Locate Game Folder: Find your main game directory (e.g., Steam\SteamApps\common\prototype 2).
Replace Files: Place the mod's .dll or executable files into the folder where Prototype2.exe is located.
Verification: Upon launching the game, new skins and powers should appear in the "Rewards" or "Mutations" menus. Known Issues & Risks
Gameplay Bugs: Some users have reported that the DLC unlocker can break the "consume" mechanic, preventing players from absorbing certain enemies like Blackwatch soldiers.
Save Corruption: Replacing core game files may occasionally lead to save file corruption if not done correctly.
Compatibility: The mod is primarily for older PC versions and may conflict with modern graphics mods like Reshade.
For official information on DLC availability for other platforms, you can check Activision Support.
This is a crucial question. For the past decade, the official solution was to buy the "Prototype 2 RADNET Edition" on Steam. However, in late 2023 and early 2024, Activision (the publisher) delisted several older Prototype DLC packs due to server shutdowns. As of 2025:
The Prototype 2 DLC Unlocker-3DM mod is a powerful piece of modding history. It represents an era when publishers locked on-disc content behind paywalls, and crackers fought back with binary patches. For a modern PC gamer, the best advice is simple:
When it works, the mod transforms Prototype 2 from a linear 10-hour revenge story into a deep, replayable sandbox of destruction. The Bio-Bomb barrage and endless survival waves are worth the effort—just make sure you aren’t inviting digital parasites into your PC for the sake of a few cosmetic tentacles.
Stay viral, stay safe.
The Prototype 2 DLC Unlocker-3DM mod is a popular community-made tool designed to enable access to the 55 pieces of downloadable content (DLC) originally released for the game, including the "Radnet" challenges and various cosmetic and gameplay mutations. Key Features & Contents
This unlocker typically enables the following content within the game:
Radnet Access: Unlocks the series of 55 weekly challenges, events, and rewards that were originally part of the game's post-launch schedule.
Player Skins: Includes skins such as "Alex Mercer" and "Zombie Mercer."
Force Multiplier Powers: Provides access to "Warp Vortex," "Medusa's Gaze," and other unique combat abilities.
Mutations: Adds extra perks for movement, combat, and health. User Experience and Performance
Reliability: Community guides suggest the mod works well for the majority of users, successfully populating the "Radnet" menu in the Steam version.
Known Bugs: Some users report minor gameplay inconveniences. For example, when in a "red" (detected) state, players may find they cannot consume soldiers while standing still, requiring a jump or the use of active mutations like Claws or Whip to trigger the consumption animation.
Ease of Use: It generally involves replacing or adding specific .dll or configuration files into the game's root directory. System Requirements for Modded Gameplay
To run Prototype 2 with these additions smoothly, the standard system requirements apply:
RAM: At least 2 GB is required, though 4 GB is recommended for peak performance. Graphics: Minimum ATI Radeon HD 4850 or equivalent. Storage: Approximately 10 GB of hard disk space. DirectX: Version 9.0C or later.
For a step-by-step installation walkthrough, many players refer to the How to Unlock Missing DLCs Guide on the Steam Community hub. Prototype 2 on Steam
Introduction
The "Prototype 2 DLC Unlocker" is a modification (mod) created by 3DM, a well-known group in the gaming community that develops and releases mods for various games. The mod in question is designed for the game Prototype 2, an action-adventure game developed by Radical Entertainment and published by Activision. Released in 2012, Prototype 2 allows players to control James Heller, the son of the original game's protagonist, Alex Mercer. The game features an open-world design, enabling players to explore and interact with the environment in various ways.
Understanding DLC and its Impact on Gaming Prototype 2 DLC Unlocker-3DM mod
Downloadable Content (DLC) has become a significant aspect of the gaming industry. DLC refers to additional content that can be downloaded and added to a game after its initial release. This content can range from new levels, characters, and game modes to more substantial expansions that add considerable gameplay mechanics and narratives. While DLC can enhance the gaming experience by providing more variety and replay value, it can also be a source of frustration for players who feel that the base game is incomplete or that the additional content should have been included in the initial release.
The Role of Mods in Gaming
Mods are community-created modifications that can alter or add new content to a game. They can range from simple tweaks and fixes to comprehensive overhauls that significantly change the game's mechanics, aesthetics, or narrative. Mods are a testament to a game's community engagement and can extend the life of a game by years. They offer players a way to personalize their gaming experience, address issues not rectified by the developers, or simply try new things that the original game did not provide.
The Prototype 2 DLC Unlocker by 3DM
The Prototype 2 DLC Unlocker mod by 3DM is designed to unlock all the downloadable content for Prototype 2, making it accessible without the need to purchase or download it through official channels. This mod caters to players who wish to experience all aspects of the game without restrictions. By unlocking the DLC, players can access new characters, missions, and other content that was previously available only through purchase.
Implications and Considerations
The use of DLC unlocker mods raises several questions regarding their implications on the gaming industry, game development, and community. On one hand, such mods can be seen as a way for players to access content they might not have been able to afford or access otherwise. On the other hand, they can also undermine the business model of game development, where DLC sales contribute to the revenue stream that supports ongoing game development and support.
Conclusion
The Prototype 2 DLC Unlocker by 3DM mod represents a common practice within the gaming community, where players seek to enhance or alter their gaming experience through community-created modifications. While such mods can offer players more flexibility and access to additional content, they also raise important questions about game development, the value of DLC, and the relationship between game developers, publishers, and the gaming community.
Future Directions
The future of game modding and DLC seems intertwined with the evolving business models of the gaming industry. As games become more complex and as community engagement becomes more crucial, developers might adopt more inclusive approaches to content creation and distribution. Community feedback and modding communities may play a more significant role in shaping the games we play and how we experience them.
The discussion around mods like the Prototype 2 DLC Unlocker and their implications will continue to be relevant as the gaming industry evolves. Balancing the interests of game developers and publishers with those of the gaming community will be crucial in fostering healthy, engaged communities around games.
References
Prototype 2 DLC Unlocker by 3DM is a classic "legacy" mod for the 2012 open-world action sequel. While official support for the game has long since ended, this small utility remains a staple for players who want the full "Heller" experience without the hurdles of defunct storefronts. 🕹️ What Does the Unlocker Do? In the original release of Prototype 2
, several power-ups, skins, and challenges were locked behind pre-order bonuses or separate digital purchases. The 3DM unlocker modifies the game's save data or configuration files to grant immediate access to: RADNET Content:
Access to over 55 pieces of content, including events and challenges. The Colossal Mayhem Pack:
Includes the Thermobaric Launcher and new skins (like Scorched James Heller). The Excessive Force Pack:
Grants the Viral Detector and the "Force Multiplier" powers.
Unlock Alex Mercer, Infantry, and various armored variants of Heller. 🛠️ How it Works (Technical Overview) The unlocker is not a massive overhaul but a configuration bypass File Replacement: It typically involves placing a specific 3DMGAME.ini file into the game directory. Profile Spoofing:
It tricks the game into believing the player has an "Elite" account or has verified all purchase licenses locally. Compatibility:
It was designed primarily for the initial PC release versions; modern Steam or "Gold Edition" versions often include this content by default, making the mod redundant for some. ⚠️ Important Considerations Antivirus Flags:
Because the 3DM unlocker uses DLL injection or modified scripts, many antivirus programs flag it as a "False Positive." Save Data Risk:
Using unlockers can sometimes corrupt existing save files. It is always recommended to back up your save folder (usually found in Documents/Activision/Prototype 2 The "Black Screen" Bug: A common issue with Prototype 2
on modern PCs is crashing or a black screen. This is usually a hardware threading issue, not a fault of the unlocker itself. 🔍 Why People Still Use It The primary reason is game preservation
. As licensing agreements for older games expire, DLC often disappears from digital stores. For many fans, the 3DM unlocker is the only way to play with the Alex Mercer skin or the high-tier that were once restricted to limited-edition buyers.
If you are planning to install this, I can help you troubleshoot if the game acts up. Would you like to know: How to fix the crashing issue on modern Windows 10/11 PCs? Where to find your save game location to keep it safe? A list of the best mutations to pick once they are unlocked?
Prototype 2 DLC Unlocker (often associated with the 3DM group) is a mod designed to enable the "Colossal Mayhem" and "Excessive Force" DLC packs on PC, which were originally hidden in the game's files but not officially released for purchase on that platform. Unlocked Content
Installing this mod grants access to several skins, powers, and game modes typically found in the Radnet -> Rewards Colossal Mayhem Pack:
Includes the Thermobaric Boomstick, Warp Vortex, Anti-Gravity Field, and multiple Heller skins (Infected, Test Subject, Infantry). Excessive Force Pack:
Adds the Viral Infector Grenade Launcher, Medusa’s Wrath, Shockwave, and several Mercer skins (Armored, Agile, Zombie). Chaos Creator Mode: A special mode included in the Excessive Force pack. Installation Guide Before proceeding, it is recommended to perform a clean install of the game to avoid file conflicts. Download and Unpack:
Locate a reliable source for the DLC Unlocker files (often found on community sites like the PCGamingWiki Prototype 2 page ) and extract the contents. Locate Game Directory: Open your Prototype 2 installation folder. Example Path: Steam\SteamApps\common\prototype 2 Copy Files:
Copy all the extracted files and paste them directly into the folder where Prototype2.exe is located. Verify Activation: Launch the game and check the Radnet -> Rewards section to see if the new skins and powers are available. Steam Community Troubleshooting & Known Issues Consumption Bug:
Some users report that the mod can prevent James Heller from consuming certain enemies, such as Blackwatch soldiers, especially when they are in an "alert" state. Dismemberment Issues:
There are reports that installing the unlocker may disable the game's dismemberment physics. Texmod Integration: If you are using additional skin mods via , you may need to rename your executables (e.g., renaming Texmod.exe Prototype2.exe ) to get them to work together. [Prototype 2] Colossal Mayhem DLC Pack | Review
Prototype 2 DLC Unlocker (often associated with groups like ) is a mod/patch designed to unlock the Colossal Mayhem Excessive Force
DLC packs on the PC version of the game. These packs were originally console-exclusive or difficult to access on PC because they were never officially sold on the Steam store Key Features Unlocked
The unlocker grants access to content that is technically already in the game files but disabled for most PC players: Steam Community Player Skins
: Includes skins like Infected Heller, Alex Mercer (classic), and others.
: Powers like "Air Time" (infinite glide) and "Warp Vortex". Force Multipliers
: Specialized weapons and buffs like the "Thermobaric Boomstick". Installation Method
Most versions of this mod (including the 3DM variant) follow a simple "drag and drop" process: the unlocker archive (often named enable_dlc.zip or similar). the files into the main Prototype 2 root directory prototype2.exe is located). Run the game
and check the "Radnet" or "Player Skins" menu to confirm the items are available. Common Issues & Tips TexMod Compatibility : If you use
for high-definition texture mods, you may need to rename your executables (e.g., renaming TexMod.exe prototype2.exe Prototype 2 remains a cult classic in the
) to get both the DLC and the textures to work simultaneously. File Integrity : If you use Steam's "Verify Integrity of Game Files"
feature, it will likely delete the unlocker files, requiring you to reinstall the mod. : Since these "unlockers" often involve modified
files from third-party groups, always scan downloads for malware before installing. or help with a specific technical error during installation?
I’m unable to create an article that promotes or provides instructions for using cracks, DLC unlockers, or pirated content like the “Prototype 2 DLC Unlocker-3DM mod.” These tools bypass paid content and DRM, which violates copyright laws and the terms of service for most gaming platforms.
If you’re interested in legitimate ways to enjoy Prototype 2, I can help with:
Let me know which of these would be useful to you.
Prototype 2 DLC Unlocker-3DM Mod Report
Introduction
The Prototype 2 DLC Unlocker-3DM mod is a modification designed for the 2012 action-adventure game Prototype 2, developed by Radical Entertainment and published by Activision. This mod, created by 3DM (a group known for their work in game modding and cracking), aims to unlock all the downloadable content (DLC) available for Prototype 2, providing players with access to additional game content without the need for purchasing it separately.
Overview of Prototype 2
Prototype 2 is the sequel to the 2009 game Prototype. The game continues the story of Alex Mercer, now seeking revenge against the Blackwatch organization and the military for their pursuit of him. The game features an open-world design, allowing players to explore and interact with a dynamic environment.
DLC for Prototype 2
The DLC for Prototype 2 includes additional characters, upgrades, and game modes. One of the main DLCs is the "Character Pack", which introduces new characters that can be controlled: James Heller and Elizabeth Kress. These characters come with their own storylines and abilities.
The 3DM Mod: Prototype 2 DLC Unlocker
The 3DM mod is designed to unlock all the available DLCs for Prototype 2. This includes:
Key Features of the Mod
Technical Details
Installation and Usage
Ethical and Legal Considerations
The use of mods like the Prototype 2 DLC Unlocker-3DM can raise ethical and legal questions. While modding communities often contribute positively to game longevity and creativity, bypassing DLC purchases can deprive game developers of revenue. Additionally, modifications can potentially violate game usage agreements and copyright laws.
Conclusion
The Prototype 2 DLC Unlocker-3DM mod offers a way for players to access all the DLC content without purchasing it. While it presents an alternative for players who wish to experience all aspects of Prototype 2 without additional cost, it also poses questions about game modding, intellectual property rights, and fair compensation for game developers.
Recommendations
Disclaimer
The information provided in this report is for educational purposes. Users should be aware of and comply with the legal and terms of service implications of using such mods.
The "Prototype 2 DLC Unlocker-3DM mod" is a modification created by the 3DM game cracking and modding group. To understand the context and implications of this mod, let's dive into what it does and the background of the game and modding community.
Prototype 2: The Game
"Prototype 2" is an action-adventure game developed by Radical Entertainment and published by Activision. It was released in 2012 for PlayStation 3, Xbox 360, and Microsoft Windows. The game is the sequel to the 2009 game "Prototype." It continues the story of Alex Mercer, now known as the Prototype, as he seeks revenge against the military and a new bioterrorism threat.
DLC and Game Content
The game had several pieces of downloadable content (DLC) that added new features, characters, and game modes. These DLCs were designed to enhance the gaming experience, offering additional challenges and storylines.
The Role of 3DM and Modding Community
3DM is a well-known group within the gaming community, particularly for cracking game protections and creating mods. Their work often allows for game localization, fixes for bugs, and, in some cases, the creation of mods that can alter or enhance gameplay.
Prototype 2 DLC Unlocker-3DM Mod
The "Prototype 2 DLC Unlocker-3DM mod" is a modification that allows players to access all the DLC content without needing to purchase it. This mod essentially unlocks all the additional downloadable content, providing players with a comprehensive experience of the game without the need for separate DLC purchases.
Implications and Controversies
The use of such mods can be controversial. On one hand, they allow players to access content they might not have been able to afford or access otherwise, potentially enhancing their gaming experience. On the other hand, they can deprive game developers and publishers of revenue, potentially impacting their ability to fund future projects.
Modding Community and Game Development
The modding community plays a significant role in the lifecycle of many games, often extending their lifespan and appeal. However, the relationship between modders, game developers, and publishers can be complex, balancing the creative freedom of modders with the commercial interests of game developers.
In conclusion, the "Prototype 2 DLC Unlocker-3DM mod" represents a form of community engagement with the game, offering players more content and flexibility. However, it also raises questions about game ownership, content monetization, and the value of DLCs in modern gaming. As the gaming industry continues to evolve, the dialogue between game developers, players, and modders will remain crucial in shaping the future of game development and community engagement.
The Prototype 2 DLC Unlocker (often associated with the 3DM cracking group) is a community-driven solution for PC players to access content that was technically included in the game's files but never officially released for purchase on the PC platform.
While console players could buy these packs, PC users were left with "hidden" content that could only be activated through file modification. Included DLC Content
The unlocker typically grants access to two major expansion packs: Colossal Mayhem Pack: Weapon: Thermobaric Boomstick.
Custom Skins: Heller Test Subject, Infected Heller, and Infantry Heller. No need to purchase individual DLC packs ,
Force Multiplier Powers: Warp Vortex, Anti-Gravity Field, and Air Time (allows infinite gliding). Excessive Force Pack: Weapon: Viral Infector Grenade Launcher.
Custom Skins: Armored Heller, Agile Armor Alex Mercer, and Zombie Mercer.
Force Multiplier Powers: Shockwave, Chaos Creator Mode, and Medusa's Wrath (eyeball lasers). How to Use the Unlocker
The process is straightforward but requires manual file replacement:
Download: Obtain the unlocker files (typically a .zip or .rar archive).
Locate Game Folder: Find your Prototype 2 installation directory (e.g., Steam\SteamApps\common\prototype 2).
Replace Files: Extract and paste the unlocker files into the folder where Prototype2.exe is located.
Verify: Launch the game; the new skins and powers should appear in the appropriate menus. Known Issues & Side Effects
Using this specific mod can introduce several gameplay bugs that users should be aware of: [Prototype 2] Colossal Mayhem DLC Pack | Review
Prototype 2 DLC Unlocker (3DM) is a community-released modification designed to enable "hidden" downloadable content on the PC version of Prototype 2
. While this content was officially released for consoles, it was largely inaccessible on PC through standard purchasing methods. Core Functionality
The mod unlocks two major DLC packs that were already present in the game's local files but remained dormant: Colossal Mayhem Pack:
Adds the Thermobaric Boomstick weapon, three Heller skins (Test Subject, Infected, Infantry), and force powers like Warp Vortex and Anti-Gravity Field. Excessive Force Pack:
Adds the Viral Infector Grenade Launcher, three additional skins (Armored Heller, Agile Armor Alex Mercer, Zombie Mercer), and abilities like Shockwave and Medusa's Wrath. Technical Implementation Installation:
Users typically download a compressed file (often from community sites like the PCGamingWiki
) and extract the contents directly into the main game directory where prototype2.exe is located.
Once installed, the new content is generally found under the Radnet -> Rewards menu in-game. Critical Issues & Limitations
While effective for unlocking content, users have reported several persistent bugs: Consumption Bug:
The most significant issue is a glitch where players can no longer "consume" certain enemies (particularly Blackwatch soldiers) unless they are in a stealth state or using specific mutations. This can make some story missions nearly unplayable. Dismemberment Loss:
Some users reported that replacing original files with the unlocker disabled the game's dismemberment physics. Workarounds: Community members often recommend using external tools like
or CheatEngine to enable "Ghost Mode" to bypass consumption issues. Safety & Legitimacy Scans of common community versions (such as the one on PCGamingWiki
) generally come back clean, though some antivirus software may flag the unlocker as a "false positive" due to its nature as a game crack/modifier. Legal Note:
The Prototype 2 DLC Unlocker-3DM mod is a fan-made tool designed to enable the Colossal Mayhem and Excessive Force DLC packs for the PC version of Prototype 2, content that was originally hidden in the game files but never officially released for purchase on Steam. DLC Content Overview
Using this unlocker grants access to several powerful items and cosmetic skins through the Radnet rewards menu:
Colossal Mayhem Pack: Includes the Thermobaric Boomstick weapon, special "Force Multiplier" powers like Warp Vortex and Anti-Gravity Field, and unique skins such as Infected Heller and Heller Test Subject.
Excessive Force Pack: Adds the Viral Infector Grenade Launcher, the Shockwave ability, and fan-favorite skins like Armored Heller and Agile Armor Alex Mercer. Critical Technical Issues
While the mod successfully unlocks the content, it is known to cause significant gameplay bugs on the PC version:
Absorption Glitch: A common and severe issue where players can no longer "consume" certain enemies (specifically Blackwatch soldiers). This can make certain story missions unplayable, as consuming targets is often a mandatory mission objective.
Dismemberment Loss: Some users report that installing the unlocker removes the game's limb-dismemberment gore effects.
Suggested Workaround: Reviewers from the Steam Community suggest installing the mod only after completing the main campaign, or keeping a backup of original files to swap back during glitched missions. Installation and Safety
Process: Installation typically involves pasting the modified files directly into the game's root directory where Prototype2.exe is located.
Risk: As with any third-party "unlocker" for paid content, there is a technical risk of file corruption. While users generally report the files themselves are safe, the resulting gameplay bugs are the primary concern.
Legitimacy: Because these DLCs are not officially purchasable on Steam for PC, this mod is often the only way for PC players to access the content that console players received in the Prototype Biohazard Bundle. AI responses may include mistakes. Learn more [Prototype 2] Colossal Mayhem DLC Pack | Review
I can still write a safe, informative article that covers legal and ethical aspects, mod history, technical background at a high level, community impact, and where to find legitimate DLC or modding resources. Here are a few angles I can take — pick one:
Which angle would you like? Or tell me any specific points you want included (tone, length, audience).
Disclaimer: This mod modifies the game’s Prototype2.exe and registry keys. Always scan downloaded files with antivirus software. This guide assumes you have a legitimate or archival copy of Prototype 2 for PC.
When Radical Entertainment released Prototype 2 in 2012, it delivered a brutal, satisfying power fantasy. Players stepped into the mutated boots of Sgt. James Heller, tearing through the zombie-like infected and Blackwatch soldiers of a quarantined New York City. However, like many games of that era, a significant chunk of content was locked behind pre-order bonuses, retailer-exclusive DLC, or platform-specific packs.
For years, PC players who wanted the complete "RADNET Edition" experience faced a wall. That is, until the modding community—specifically the legendary Chinese group known as 3DM—stepped in with a solution: the Prototype 2 DLC Unlocker-3DM mod.
This article provides a comprehensive guide to what this mod is, what DLC it unlocks, how to install it safely, and whether it is the right choice for your playthrough.
Copy the files. Drag all extracted contents into your Prototype 2 root installation folder. Overwrite the existing Prototype2.exe when prompted.
Run the Registry Patch. Inside the mod folder, right-click on Add_DLC.reg (or similar) and select Merge. Confirm the warning. This tells Windows that your account owns the DLC.
Launch the game. Start Prototype 2 via the new Prototype2.exe (not through Steam, as Steam may try to "fix" the file).
Using the Prototype 2 DLC Unlocker-3DM mod is a violation of the Digital Millennium Copyright Act (DMCA) in the US and similar laws globally. You are circumventing a technological protection measure (Steam’s DLC authentication).
However, ethically, the debate is murky. Since Prototype 2 is no longer supported by Radical Entertainment (which closed in 2017), and Activision shows zero interest in updating the game, many players argue that unlocking DLC for a 13-year-old game is "abandonware ethics." You are not stealing a product that is actively sold as a separate DLC; you are simply enabling content that is already on your hard drive.