The game is still being sold by Activision despite not being fully compatible with either Windows 10 or Windows 11. And by "not being fully compatible," I mean you can't actually play the game without applying certain fixes.

There are numerous crashes when launching the game. The fix is quite simple, though not very easy to find on Steam's P2 forums. So here it is, to save you the hassle of searching for it.

The fix was created by Emoose. It's relatively small and hosted on the Nexusmods website. You’ll need to have an account to download it.

• Mod descriptions and instructions[www.nexusmods.com]
  
• Mod download page[www.nexusmods.com]

Installing the fix is straightforward:

• Unzip the file
  
• Paste its contents into the root of the installation folder, next to the Prototype2.exe file.
  The folder path should look something like C:\Program Files (x86)\Steam\steamapps\common\Prototype 2
  
• Tweak the prototype_fix.ini file with any desired changes—or leave it as is.
  
• Enjoy the game!

There may still be problems in some missions. I personally encountered one during Operation Fly Trap.
You can find straightforward fixes for these issues in this guide.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2834535362