Arma 3 is the ultimate modern combat simulator.

Warframe is a free-to-play third-person shooter with the polish of a paid title. One of its best features is its numerous game types and play styles.

Verdun is a great game for cooperative play with small groups.

Hearts of Iron III is a wonderful strategy simulation focused on World War II statecraft in its full complexity.

Men of War: Assault Squad 2 is an RTS strategy game that models brigade level WWII conflicts. It is incredibly challenging for even veteran strategists.

If you like blowing people up for no reason and want a guilt-free way to do it, buy this game.

It's great for LAN party style multiplayer.

If you want an immersive, historically accurate WWII FPS, then Rising Storm/Red Orchestra 2 Multiplayer is your best bet.

Barony is a great game for LAN party style multiplayer, dungeon crawling, hack-and-slash action.

Mount & Blade: Warband is an excellent game that caters to many different tastes through it's enormous modding community.