The warehouse puzzle, in your browser. You can only push boxes, never pull them, and only one at a time — so a crate shoved into a corner or against a wall is often stuck for good. Plan before you shove. The level is solved when every goal square is covered.
Stuck or sloppy? Undo as far back as you like, or reset the level and start fresh. Your current level is remembered between visits, and the URL carries it too, so you can bookmark or share an exact spot.
Sokoban
Arrow keys or WASD to move. U undo, R reset. Click a free square to walk there. Levels from xsokoban 3.3c.