GRave Defense HD Free is the next step in the evolution of tower defense games. Follow the harrowing encounters of the Fellowship of Survivals as you battle mutated zombies and formidable boss monsters. GRave Defense HD Free is: - 11 HD Levels + 37 HD Levels unlockable - achievements, enemies and towers! - Military Ranks! Climb the militant ladder, all the way to the "Top"! - Survival mode: - More tower upgrades! - Earn more points and get the High Score! - Online ranking system!