Ozvenka: Echo Deduction

Listen. Deduce. Never guess.

Free · In‑App Purchases · Designed for iPad. Not verified for macOS.

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.

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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.

Version 1.0.3

The developer, Web 3.0 s.r.o., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

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    Accessibility

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    Information

    Seller
    Web 3.0 s.r.o.
    Size
    2.2 MB
    Category
    Puzzle
    Compatibility
    Requires iOS 15.0 or later.
    • iPhone
      Requires iOS 15.0 or later.
    • iPad
      Requires iPadOS 15.0 or later.
    • iPod touch
      Requires iOS 15.0 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English and 2 more
    • English, Czech, Slovak
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Drozd Studios
  • Developer Website
  • Privacy Policy

    • Supports

    • Family Sharing

      Some in-app purchases and subscriptions may be shareable with your family group when Family Sharing is enabled. Learn More

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