Ozvenka: Echo Logic Puzzle

Ozvenka is a quiet logic puzzle about listening.

The cave is dark. Stones lie somewhere inside it and you will never see them. You put nothing into the cave — you send an echo in from the edge and listen for where it comes out. Either it appears somewhere else, or a stone swallows it, or it returns the way it went. From what you hear, where the stones lie can be worked out. Not guessed. Worked out.

• 120 caves across ten worlds, plus a daily cave — one a day, the same one for everyone
• Every cave's par is the smallest possible number of echoes. It is not the author's estimate: the same solver that verified the cave computes it
• You never have to guess: every cave has exactly one answer, and the echoes can always settle it
• When you get it wrong, the game says why: whether an echo contradicts your reading, or whether you simply have not heard enough yet
• The hint is computed from what you have actually heard. It never points at something that is not in the cave
• Once you solve it, you see where the echoes really went
• Slovak, English and Czech

No ads. No accounts, no sign-in.

Gameplay works offline: every cave and every daily is inside the app, so it plays on a plane. Gameplay statistics stay on your phone. Purchasing and restoring need a store connection.

The optional Moonlit Hall adds 60 new caves with a one-time purchase. The original 120 caves, daily challenges, guided introduction and hints stay free.