Flappy is a puzzle game. Gravity, gaps in the floors, and wandering enemies stand in the way of Flappy reaching his goal. Flappy can pick up and throw sleeping mushrooms at the enemies to knock them out for a while, or drop stones on them to crush them permanently. There are, however, many obstacles along the way: brick walls you must work your way around, brown stones which you can crush but which can also crush you if they fall on you, holes or dead angles in which the blue stone becomes unretrievable if it falls into them, and moving enemies. The game features just two enemies: Unicorns and Ebira. Unicorns are green creatures that move in mostly-repetitive horizontal patterns. Ebira are red crab-like enemies (the word "ebi" is a Japanese term for shellfish) that relentlessly chase Flappy both horizontally and vertically. Ebira tend to mimick Flappy's movements, so Flappy must be careful to avoid being charged by a persistent Ebira.