CastleStorm combines castle building, physics-based siege combat and tower defense. Each side has a fortress, and you design your own from blocks and rooms, then try to knock down the enemy's walls with a ballista and other siege weapons. Meanwhile you send troops onto the field and can step in directly as a hero to fight on the ground.
The mix of aiming, building and unit management keeps battles varied and fairly quick. There is a story campaign for single players, plus multiplayer for playing with or against others. CastleStorm suits players who like lighthearted strategy with a hands-on action element and enjoy watching structures fall apart under fire.