To unlock the Armored Heller skin, you need to complete the main storyline of Prototype 2. This means finishing all the main missions and quests, including the final mission. Completing the main storyline will give you access to the game's side missions and other unlockables.
Prototype 2 - Armored Heller Skin - (Excessive Force Pack DLC) prototype 2 how to unlock armored heller skin
Save your 100% game. Then, return to the main menu and select "New Game+" (if available) or simply "New Game" on the same difficulty. Play through the first tutorial mission (where you fight the giant infected Monster). Once you gain control of Heller on the rooftop, pause and go to "Options" > "Extras" > "Skins." The Armored Heller skin should now be selectable. To unlock the Armored Heller skin, you need
Navigate to the RADNET menu from the pause or map screen. Prototype 2 - Armored Heller Skin - (Excessive