What causes a sliding-tile swap allowing a non-adjacent tile to move?

Clicking any tile swaps it with the empty cell without checking adjacency, so tiles teleport into the gap from across the board instead of sliding in from a neighbor.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Sliding-Tile Swap Allowing a Non-Adjacent Tile to Move

Quick answer: On click, allow the swap only if the clicked tile shares an edge with the empty cell (same row or column, one step away); otherwise ignore the input.

In a sliding puzzle only the four tiles bordering the gap can move. If clicking a tile anywhere snaps it into the empty space, you are swapping without an adjacency test. Restrict moves to the gap's orthogonal neighbors.

How to fix it

1. Compute the distance to the gap

On a tile click, compare its grid coordinates to the empty cell. The move is legal only when the Manhattan distance is exactly 1 (same row or column, one cell apart).

2. Swap only adjacent tiles

If the clicked tile is adjacent to the gap, swap their grid positions and animate the tile sliding into the empty cell. Otherwise do nothing.

3. Optionally support row/column slides

Many sliding puzzles let a click slide an entire line of tiles toward the gap. If desired, detect that the clicked tile shares the gap's row or column and shift every tile between them.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Construct 3 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.