Everbastion

Castle defense

Everbastion is a single-screen idle tower defense game for PC. Your castle sits in the middle of a plain as monsters attack from every direction. You build up its defenses between battles, then watch them fight: there’s nothing to build during a round.

The castle starts with three archer towers. As you defeat bosses, it physically grows and opens new building slots. Its shape limits where defenses can go, with each ring fitting inside the one before it. If there’s no room for a structure, you can’t place it.