How to play

Each puzzle is a grid of thermometers. Fill cells with mercury — from the bulb upward — so that every row and column clue is satisfied. Tap once to fill, tap again to mark empty, tap again to clear.

Three daily puzzles

Every day brings a fresh warm-up, daily, and challenge puzzle. Date-seeded — everyone on the same day gets the same three boards. Solve streaks are tracked locally on your device.

800 bundled levels

Eight packs, 5×5 through 12×12. Puzzles unlock chapter by chapter as you progress. New Kelvin chapters can be downloaded as you keep playing. All bundled puzzles are available offline.

Offline-first

Mercuro stores your active puzzle state on your device. Sign in with Apple is optional and can sync solved progress, streaks, purchases, and unlocks through your personal iCloud account.

Fair monetization

Mercuro is free to start. Ads can appear around extra hints and optional gates. A one-time Go Ad-Free purchase removes ads permanently and includes unlimited ad-free hints.