If you missed the pre-order window, these are usually impossible to get legally unless you buy a key code online:
Prototype 2 , unlocking skins allows you to change Sgt. James Heller’s appearance to various forms, including the iconic look of the original protagonist, Alex Mercer Prototype 2 Unlock All Skins
Did we miss a skin? If you found a secret "Debug Skin" or "Dev Build" variant, let us know in the comments. Happy consuming. Prototype 2 Unlock All Skins: A Comprehensive Guide 4