C-Virus Game: Outbreak is an awesome TPS game with the most interesting gameplay. Eliminate all the viruses, and more appear. The only goal is to survive, survive, and survive.
Not going give you any spoilers but it is something like an old resident evil series. That Should be enough to get in interested.
C-Virus Game: Outbreak was developed by Poison Games.
WASD or arrow keys to walk
Left mouse button to attack/shoot
Right mouse button to aim
F to interact with objects
Left shift to run
Left Ctrl to crouch
Space bar to jump