The enemy is not a horde. It is a river, and it is already coming.

HOLD THE CHANNEL

Tens of thousands of drops, simulated one by one, pile against your line and pour through the first gap they find. Burn them, blow them back, zap them, or drop a black hole in the riverbed and swallow the river whole.

THE MAP GIVES WAY

Moving water carves the land. Banks crumble, channels widen, and the route the flood took last time is gone. What you cannot afford to lose, you reinforce before the water arrives.

ONE FLOOD A LEVEL

Every level is a single wave. Survive it, or hold it without a drop reaching the base, and spend the points on a skill tree: seven turrets, two builds each, and four abilities, down to reversing the river itself.