Overrun: Offline Tower Defense

Overrun is zombie base defense with a gun in your hand. Put up turrets and barricades, recruit survivors, then take direct control of one and shoot the horde yourself with twin-stick controls. It plays fully offline, so you never need a connection to play. Every zombie you kill earns Z-Bucks, which you spend on upgrades between waves. There are dozens of waves, and each one pushes harder than the one before. The maps include the suburbs, a hospital and a power plant, each with its own layout and tougher enemies, so a tower defense plan that worked in the suburbs needs rethinking at the power plant. Zombie base defense starts with the base: the turrets, barricades and defensive structures you place and upgrade. Your survivors carry rocket launchers, .50 cal rifles, grenades and Molotovs, and they level up as they fight. In the middle of a wave you can call in special strikes, drop first-aid kits and pick up power-ups. This is tower defense and twin-stick shooting in one game, and both work offline. Leaderboards and achievements run through Game Center, cloud saves keep your progress safe between devices, and there are daily rewards to collect. Overrun is free to play, with optional in-app purchases.