Adventurers roll into your dungeon as balls. You lay bricks and traps so that none of them reach the treasure at the top. The moment a ball slips past the paddle and falls, the worst moment in Breakout, is the best moment here.
Triangle, round and half-round bricks bend shots in different ways; spikes, slime and fire vents chip away at each ball's health. Mid-fight you drag the guardian brick to twist angles, and one tap sets off every trap at once. The adventurers' AI paddle gets smarter with each wave.
Between waves you draft one card of three, roguelike-style. It is a prototype right now, built to test the feel. The plan is web first, then Steam and mobile.