It changes the gameplay from a survival-horror RPG to a power-fantasy shooter, and it was released as a free update for all owners of the game.
Since you mentioned "developing a feature," it’s worth noting that the developers (Teyon) actually added a massive after launch called Infiltrator Mode . Terminator: Resistance Free Game Download Full
While not strictly free, the game often sees deep discounts (up to 60-70% off) during seasonal sales, or it may appear in "Choice" bundles where the individual cost is negligible. It changes the gameplay from a survival-horror RPG