Buy Ravenfield

Ever wanted to pit armies of AI-controlled bots against each other? Ravenfield is exactly the game you need. This is a single-player first-person shooter and simulator for AI-controlled team vs. team matches. In other words, you set up the battle plan, the number of combatants, and the battlefield, then you lead your forces on an all-out brawl. 

Ravenfield lets you select how the AI behaves and how many fighters there are on both sides. You can choose to fight as infantry, or on tanks, or on ships, or in the skies. Thanks to good ol' ragdoll physics, you can enjoy the mayhem of cartoon violence as soldiers leave behind splats that match their team’s color. You can also fight with just about any weapon or artillery imaginable with the right mod installed. The only limit to the sheer number of soldiers in the game is your hardware’s capability. Beyond that, the sky’s the limit!

So if you want to play a WWII scenario using modern-day weapons, or kill Xenomorphs while playing as a Spartan from Halo, then Ravenfield is just the game to play.