2-4 player tile-laying game with simultaneous bidding for control of actions each turn. Players aim to bring their "flow" piece down the waterfall avoiding obstacles and being the first to reach the bottom. On each turn, players choose actions they wish to control: adding a path tile, moving their flow piece up to 3 tiles, adding a block on a path tile, rotating a block on a path tile, Go First, or picking the top Freak Event card. Bidding for actions is secretly carried out behind the player screen before revealing simultaneously. Players win control of an action by having the most bidding chips on its spot on the player mat. It is possible to have many actions on a single turn which may be carried out in any order.