Cheerful critters are marching up to your hill. Put towers on the grass and pop them before they reach the top. Twenty waves, twenty lives.
Popper quick shots
Plopper slow splash
Fizzer slows the crowd
Zinger long range sniper
Tap grass to build, tap a tower to upgrade or sell. Keys: 1 to 4 pick a tower, arrows move, Enter places or opens, U upgrade, S sell, N next wave, F speed, P pause, M mute.