TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.
Rust Game - Rust’s world is harsh. The environment is not kind. Bears and wolves will chase and kill you. Falling from a height will kill you. Being exposed to radiation for an extended period will kill you. Starving will kill you. Being cold will kill you.
Lux Delux - Lux Delux is a game of strategy and domination inspired by the board game Risk.
Arma - Experience true combat gameplay in a massive military sandbox.
Streets of Chaos - Streets of Chaos is a Puzzle, Tactical, Turn-based Strategy and Single-player Simulation created by SimProse Studios.
Left 4 Dead 2 - Left 4 Dead 2 remains the co-operative zombie adventure with all new characters, locations, enemies and also weapons to change in the popular game-play introduced in the unique Left 4 Dead.