Chubby Finn

Chubby Finn is a Sokoban puzzle built around one seal and a single unforgiving rule: you can push, but you can never pull. Finn waddles around a tiled room with a handful of balls scattered across it, and your job is to nudge every ball onto a marked target square. Nothing in the game is hidden and nothing is random. Every level is laid out in front of you from the first second, which means every mistake is entirely your own. That is the appeal of the Sokoban format and the reason it has outlived almost every puzzle genre invented alongside it. The difficulty does not come from reflexes or from timing. It comes from the fact that a single careless step can quietly make a level impossible to finish while everything still looks fine on screen. You will not notice the moment you lost. You will only notice several moves later, when the ball you need is sitting flat against a wall with no way to get behind it.

Each level gives you a number of balls and exactly the same number of target squares. Walk Finn into a ball to push it one tile in the direction you are facing. Move every ball onto a target and the level is complete. Finn can only push a ball if the tile directly behind it is empty, and he can only ever push one ball at a time, so two balls sitting in a row cannot be moved together. There is no undo button on the board itself and no way to reach around a ball to drag it back, which is why the order you solve things in matters far more than how quickly you move.

Treat corners as permanent. A ball pushed into a corner can never leave it, so unless that corner is a target, you have just ended the level. The same trap applies along walls: once a ball is flush against a wall, it can only slide along that wall, so if its target is not on that wall the level is already lost. Work backwards instead of forwards. Look at where each ball has to end up, then ask which side Finn must be standing on to make that final push, and whether he can actually get there. Solve the balls that sit deepest in the room first, because the ones near the entrance will block your path once they are placed. And when a level stops making sense, the problem is almost never the move you are looking at. It is a push you made four or five moves ago.