Colony Siege

Colony Siege combines the best of RTS and tower defense, including base building, mazing, and unit physics. Use shockwaves and spring traps to propel enemies into cliffs, lava, and other hazards. Build mechs, tanks, and other mobile units. Decimate massed enemies with air, missile, and orbital strikes. The expansive non-linear campaign supports single-player and 2-player online co-op throughout.

Defend against the relentless biomechanical Xeno swarm and the corrupted Riven (once human). Both enemy factions behave differently and demand different tactics. Defensive towers automatically form walls when placed near each other, generating a laser fence that allows your mobile units passage while restricting enemy movement. Slow, impale, burn, or bombard with traps; strike with satellite-powered attacks, long-range missiles, and fighter sorties.

The starmap features dozens of intense missions with branching paths. Press your advantage or replay previous missions for extra cash. The entire campaign is cooperative from start to finish. Persistent progression earns money from primary and bonus objectives, spent on upgrades, new weapons, and varied towers/traps/units/strikes. Battle across different planets, moons, space stations, and enormous mobile space platforms.