Fossil Sweep A free minesweeper puzzle at a fossil dig
Dig a fossil site with number clues and plant flags on collapsed tunnels. Every board is solvable by logic alone, and every find builds a museum skeleton.
About Fossil Sweep
Fossil Sweep is a free online minesweeper-style logic puzzle with an archaeology twist, playable in your browser on a phone, tablet or computer. You are digging a fossil site made of sandstone tiles. Some tiles hide collapsed tunnels. Dig a safe tile and it shows a number: how many tunnels touch it, counting the eight tiles around it. Use the numbers to work out which tiles are safe to dig and which hide a tunnel, and plant a flag on every tunnel. Dig every safe tile and the site is cleared.
The big difference is that you never have to guess. Every site is checked by a solver before you see it, and the solver may only use reasoning a person can use: a single clue, two overlapping clues compared with each other, and the tunnels-left counter. Your first dig is always safe and always opens an area, and from there the numbers always lead to another sure move. If you are ever unsure, the Hint button points at a tile that is provably safe and glows the clue that proves it, for a small score cost.
Fossils make every dig worth finishing. Some safe tiles hide a fossil piece. Dig one and it sparkles and flies to the museum. There are eight skeletons to assemble, from a Tyrannosaurus and a Triceratops to a Mammoth and an Archaeopteryx, each made of six pieces. Pieces are chosen from the ones you do not own yet and always finish the skeleton that is closest to complete, so you see progress after every site. Pieces are banked when you clear the site, so a collapse never costs you your collection.
Three sites are waiting every day: Easy (8 by 8 with 10 tunnels), Medium (10 by 12 with 20) and Hard (12 by 16 with 36). Everyone in the world gets the same three sites on the same UTC day, with the entrance already dug, so you can compare times with friends. Clear any daily site to keep your streak going, and use Free dig for as many extra sites as you like. Stars depend on your time, collapses and hints, and your score counts a time bonus, fossils found and penalties for mistakes.
On a phone, tap a tile to dig it and press and hold to plant a flag; a ring fills around your finger while you hold. Prefer a toggle? Switch to Flag mode and a tap plants flags instead. Tap a number whose flags already match it to dig all its other neighbours at once, which is the fastest way to open an area. On a computer, click to dig, right-click to flag, or use the arrow keys, Space, F, H and X. If a tunnel collapses, one tap retries the same site, and you can watch an optional short ad to shore up the tunnel and keep digging once per site.
Tips: start with ones next to a wall of tiles, because a 1 with only one unknown neighbour is a sure tunnel. When two clues share tiles, compare them: if one needs one more tunnel than the other, the tiles only it touches must hold it. Watch the tunnels-left counter near the end. And on Hard, drag the site to pan around it. Progress, streaks and your museum are saved on this device, and to your account when you are signed in.
How to play
Tap a tile to dig it. A number tells you how many collapsed tunnels touch that tile. Press and hold a tile (a ring fills up), or switch to Flag mode, to plant a flag where you know a tunnel is. Tap a number whose flags match it to dig all its other neighbours at once. On a computer, click to dig and right-click to flag; arrow keys or WASD move a cursor, Space digs, F flags, X switches mode, H gives a hint and U opens the museum.
Controls and devices
- Controls: Touch, Mouse, Keyboard
- Works on: phones, tablets and computers
- Screen: portrait orientation
- Price: free, no download or sign-up
FAQ
- Do I ever have to guess?
- No. Every site is checked by a solver that only uses logic a person can follow, and your first dig is always safe. If you are stuck, the Hint button shows a tile that is certainly safe.
- How do the daily sites work?
- Every day at midnight UTC there are three new sites (Easy, Medium and Hard), the same for every player, with the entrance already dug. Clearing any of them keeps your daily streak going.
- What are the fossils for?
- Some safe tiles hide fossil pieces. Eight museum skeletons need six pieces each. Pieces you find are banked when you clear the site, and you never find a piece you already own.
- What happens when a tunnel collapses?
- The site shakes and shows every tunnel. One tap on Try again restarts the same board. Once per site you can watch an optional ad to shore up the tunnel and keep digging.
- How do I plant a flag?
- On a touch screen, press and hold a tile until the ring fills, or switch to Flag mode and tap. On a computer, right-click the tile or press F.
- What does chording do?
- Tapping a number whose flags already match it digs all of its other neighbours at once. It is the quickest way to open an area, but a wrong flag will cause a collapse.
- Is my progress saved?
- Yes. Your streak, museum, stats and any site in progress are saved on this device, and to your account when you are signed in.
Credits
- Game design, code, art and sound: Playora Games