1 · Drums march the loopEnemies are drum sounds. They spawn at the top and walk clockwise, forever, until you kill them. Every lap through the gate costs a heart.

2 · Build from your handTower cards are dealt from your deck. Click a slot next to the road to build the selected card. Towers wear out over the loop; the thin line under a tower is the time it has left. Slots are notes: layouts that sound right unlock combos.

3 · Shop between loopsAfter each loop the towers are wiped and you keep the coins. Buy passives (up to 5) and stronger tower cards for your deck.

4 · Ten loopsEvery loop the drums get tougher. Survive loop 10 and the run is yours. Drop to 0 hearts and the speaker blows.