How to Play Glide
Glide is a classic 15-puzzle sliding tile game rendered with frosted glass aesthetics. A 4x4 grid holds 15 numbered tiles and one empty cell. Your goal is to slide tiles into the empty space, one at a time, until all tiles read 1 through 15 from left to right, top to bottom, with the empty cell in the bottom-right corner.
To move a tile, click or tap any tile that directly shares an edge with the empty cell — the tile moves into place immediately with a soft click and a small burst of particles. Diagonal tiles and tiles two steps away cannot move. On a touch device, you can also swipe across the grid in the direction you want the empty cell to move. On a keyboard, use the arrow keys to slide tiles in the direction of the empty cell.
The puzzle tracks every move and runs a timer from your first slide. Your score is based on how few moves you use compared to par — 25 moves for 3×3 Easy, 80 for 4×4 Classic, 200 for 5×5 Hard. Solving in 50 moves on the 4×4 earns 300 points; solving in exactly 80 earns 0. The leaderboard ranks players by highest score, so the premium is on efficiency, not just completion. Each difficulty has its own leaderboard: switch between 3×3 Easy, 4×4 Classic, and 5×5 Hard using the size selector above the grid.
Earn Insight Tokens for every solve — at least 1 per puzzle, more for efficient solves under par. Spend tokens in the Tech Tree to unlock permanent upgrades: undo slots let you reverse last slides, hint flashes highlight a good next move. Unlock Undo I first (5 tokens) to switch the Undo button on — you can then take back one slide per puzzle, invaluable when you realize a sequence of moves is heading toward a dead end; Undo II (15 tokens) raises that to three undos per puzzle. Hint I (10 tokens) shows the best adjacent tile to move by highlighting it in blue; Hint II (25 tokens) gives three hints per puzzle for those especially tangled scrambles.
Strategy Guide
Expert sliding-tile solvers use a two-phase approach: first solve the top two rows by placing tiles 1 through 8 in their goal positions, then solve the remaining 2×4 section using a standard L-shaped rotation sequence. On the 4×4 grid, the top row (tiles 1–4) can be solved by parking tile 1 in the top-right corner temporarily, rotating it into place last. Never solve tiles 3 and 4 independently — they must be placed together with a coordinated 3-move rotation to avoid stranding one or the other. For the 3×3 Easy mode (8-puzzle), look up the goal-distance heuristic: sum each tile's Manhattan distance from its goal position. A lower total distance means you're closer to the solution — tracking this mentally helps you evaluate whether a sequence of moves is making progress.
The daily challenge is also a great way to build a solving streak. Each day's puzzle uses the same seed for every player, so everyone on a given grid size shares a common scramble. Solve the daily challenge first each day before starting free play — it preserves your streak and keeps the leaderboard contest meaningful. A 7-day streak pops a "7-Day Streak!" milestone banner and signals mastery of the puzzle at any difficulty level you choose. If you're aiming for leaderboard positions, note that free play keeps a separate board per size: the 3×3 Easy board has par 25, so a 20-move solve scores 50 points — a friendly target for new players getting a feel for the mechanics before tackling the 4×4. The daily challenge is the exception; every size posts to one shared daily board, so a 4×4 or 5×5 daily solve has far more score headroom than a 3×3 one.
Controls
- Click / Tap tile: Slide that tile into the adjacent empty cell
- Arrow keys: Slide the tile in the direction of the empty cell (Left = slide tile left of empty rightward into empty)
- U: Undo last move (requires Undo I or II from Tech Tree)
- H: Highlight a hint tile (requires Hint I or II from Tech Tree)
- N: Start a new random puzzle
- D: Start today's daily challenge
- M: Toggle sound mute
- Touch swipe: Swipe direction on the grid to slide the relevant adjacent tile
Puzzle Mechanics and Solvability
Not every arrangement of 15 tiles is solvable. A scrambled 15-puzzle is solvable if and only if the inversion count and the blank tile's row distance from the bottom have opposite parity — that is, only if the two added together come out odd. Glide's shuffle generator verifies this automatically using an inversion-count check and reshuffles until a valid scramble is produced — typically on the first or second try. You will never be handed an unsolvable puzzle.
The daily challenge uses a seeded random number generator (mulberry32) keyed to the current date string, producing the same starting scramble for every player who plays it at the same grid size on that calendar day. This makes the daily challenge a fair, shared experience regardless of when during the day you play it.
Frequently Asked Questions
How do you move tiles in Glide?
Click or tap any numbered tile that shares a row or column edge with the empty cell. That tile slides into the empty space. Non-adjacent tiles (diagonal or two steps away) do nothing when clicked. On mobile, you can also swipe on the grid in the direction you want the empty cell to travel, and the tile it lands on slides across. Keyboard arrow keys also work: press Left to slide the tile to the left of the empty cell rightward into the empty slot.
What is the daily challenge mode in Glide?
The daily challenge generates a fixed puzzle seeded from today's date, so every player on the same grid size solves the same scramble that day. Your completion is saved locally and cannot be replayed the same day. A correct daily solve increments your daily streak counter. If you miss a day, the streak resets. Access it via the Daily (D) button or keyboard shortcut D.
What are Insight Tokens and the Tech Tree in Glide?
Insight Tokens are earned on every puzzle solve — at least 1 per solve, with bonus tokens for efficient solves under par. Spend them in the Tech Tree (press the Tech Tree button) to unlock permanent upgrades. Undo I (5 tokens) gives 1 undo slot per puzzle; Undo II (15 tokens) upgrades to 3 slots. Hint I (10 tokens) grants 1 hint flash per puzzle to highlight a good next move; Hint II (25 tokens) gives 3 hints. All upgrades and token balances persist across sessions.
How is the Glide score calculated?
Score = max(0, PAR - moves) x 10. For the 4x4 grid, PAR is 80 moves. Solving in 60 moves scores 200 points; solving over par scores 0 (no penalty). The score is submitted to the leaderboard so you can compare move-count efficiency against other players. The 3x3 easy mode has PAR 25 with its own leaderboard.
Can you undo moves in Glide?
Yes, but only after unlocking Undo I (5 tokens) from the Tech Tree; Undo II (15 tokens) is the next node above it. Use the Undo button or press U to reverse the last slide — the move counter drops back by one as it does. Undo history keeps the last 10 board states, but each puzzle only spends the undo slots you have unlocked: one undo with Undo I, three with Undo II.
