We cannot stop a determined cheater on a browser puzzle game. Here is what we actually do, and where the limits are.
It would be easy to write a paragraph claiming we have solved cheating on a browser puzzle site. We have not, and no one has. The code runs on the player's machine.
What we have instead is a set of measures that raise the cost of cheating and keep the leaderboard useful for everyone else.
The server regenerates every board
Because puzzles are derived from a seed, our server can rebuild the exact board you played and check that your claimed result is consistent with it.
This catches the easy cases: fabricated times, impossible scores, results that contradict the board.
Losing focus marks the run unranked
If you switch tabs mid-puzzle, we assume you may have looked something up. The run is stored, but it does not enter the leaderboard.
This is deliberately conservative — it will occasionally flag an innocent interruption, and we think that is an acceptable price.
The honest limit
Someone who writes a solver that plays the board without leaving the tab will pass every check we have. That is a real limit and we are not going to pretend otherwise.
What we can promise is that the leaderboard reflects runs we could reproduce. For a daily puzzle that most people play for their own satisfaction, that is enough.