As requested by Allack, posting my review here so it can be replied to.
Unfortunately, that's where the positive points end. Puzzle design aside, nearly every single aspect of this game is ruined by shoddy interface and fearsome bugs.
The ability to undo moves, while very welcome, is so horribly broken that dozens of user-created levels have been made to illustrate all the different ways it can be abused.
Various timing bugs exist in the game which make hunting for the #1 score on the leaderboard pointless. While it is welcome that the game rewards you for even tying the high score, the high score was usually acquired by someone’s lucky run where the timer skipped, started too late, or a rewind glitch was used.
Menus are clearly optimized for touchscreens and are downright difficult to control with a mouse, as an invisible timer will always cause the cursor to leap back to the beginning of the list every few seconds unless you use the mouse to "drag" the screen horizontally.
Thumbnail screenshots for user-designed levels are a disaster, as they frequently change, resize themselves, disappear, and even appear on the incorrect levels. Stats and leaderboards for user-created levels are inconsistent between the official site and the in-game browser; the same level will have different leaderboards and different star-rankings depending on where you look.
The level editor has an unforgivable bug which renders it incapable of telling the difference between a local copy of a level and the server-side copy. In common cases, especially when modifying a level locally after having uploaded it, you can load a level from the search engine and it will load a completely different version of the level for you than it will for other people.
While all that is annoying, the number one sin of this game is its in-game control scheme, bringing back terrible memories of slipping and sliding around in the NES version of Boulder Dash. While movement is tile-based like Sokoban, the main character moves smoothly from one tile to the next, which allows for time-based leaderboards to exist. Unfortunately, this means that if you want to make any kind of quick or complex movements, you need to press the keys a half second ahead of time. Hold the key for a millisecond too long and you’ll go sliding off your intended path and into a death trap. Whereas most Sokoban games (Like Chip's Challenge) use the keyboard buffer to delay your movements, or make the character move slow enough that you can mentally queue your movements, the main challenge of Chuck’s Challenge comes from just getting your character to move where you want, rather than the block puzzles themselves. Even though I conquered this game, I never completely got used to it, and it made in-game movements an unpleasant and frustrating experience from beginning to end. That’s just not what I want in a Sokoban game.
I’ll update this review if a patch fixes any bugs, but for now I’ll say that you should only buy this game if you appreciate block puzzles so much that brilliant level design outweighs bad controls and numerous other flaws. Everyone else should pass.
This was hard for me to downvote. I love block puzzles and I think Chuck Sommerville is a master of puzzle design. His genius lies in the simplicity and elegance of the levels. When a level is so small and has so few moving parts, you can only blame yourself for not seeing that one small element you were overlooking the whole time. I love that. I thoroughly completed this game, gaining nearly all the gold medals and single-digit rankings on roughly half of the levels; cracking the code of the simple yet devious puzzle designs brought me hours upon hours of bliss.