“Fail-Deadly” by Josh Sutphin.
“[A] simple [real-time strategy game] where you play as both sides. […] [Y]ou are a shadowy third party using two enemies against each other to achieve some secret, grander goal.”
You need to bring destruction and death to both sides, but be careful: It’s hard to balance the forces in “Fail-Deadly”. An interesting game about the absurdity of war.