This physics-based battle games has you pit two different types of units against each other.
"TABS" has you form two different types of units, spawn them into the middle of a field and then see which side survives the skirmish. This game gives you a lot of different options for units to deploy. Once both sides are satisfied with their picks, start the battle and watch what happens once they make eye contact. The battle ends when all members of one side are defeated. You have 20 levels to play through,each offering different terrain and opposing forces. You can pic as many units as your budget for purchases and head count allows it. You can also play in a sandbox mode that gives you an unlimited deployment size.
This game lets you mashup drastically different units together; you can totally deploy heavily-armored space marines with a mob of peasants wielding farm implements. The physics work well and can be used to great effect in simulating warfare. Your only direct control over the action is moving the camera about the battlefield.
Pros: Super-customizable battalions. Lots of combat scenarios.
Cons: Lacking graphics. Weird physics hiccups. Erratic crashes. Camera controls can be finicky.