If you're looking for a challenging and rewarding puzzle game, I highly recommend Box World.
Description
Box World is a Sokoban variant where the player has to push boxes to get them into designated spots. The boxes will mark in red. Once every box is on a marked spot, the player will go to the next level. Boxes can only be pushed one at a time, so two boxes next to each other cannot be pushed together. If the player gets stuck with the boxes during a level, he can make one move back (using undo), and if he fails, he will need to start the level from the beginning.