How it plays.
Build a maze. Send creeps. Outlast your rivals.

Build your road.
Place towers anywhere on your side. The creeps walk the maze you make.

Send them your worst.
Buy creeps and send them at a rival. Every one you send raises your income for the rest of the match.

Hold the line.
Every creep that slips through costs you. Leak too many and your keep falls.

Rank up.
Each tower grows along its own line. Pick the branch that beats what they send.