From now on, each time I'll play a puzzle game, I'm going to judge it based on this one !
To be quick : there is no downsides.
The game is easy to play, fun, and can keep us occupied for a while.
The levels are well balanced, they're neither too easy (and so, boring) nor too hard (if you get stuck at one point, just go to sleep and come back later).
They're varied : you have level where you just have to push block in a certain order, some with a countdown, some with enemies to evade, some where you'll have to lie back in your chair to figure your way out...
And you'll never manage to pass a level by sheer luck : you need to know what you're doing.
Everything has been well thought out, from the password of the level always on display (so you can stop whenever you want whitout thinking that you forgot to note it and will have to play the game from the start all over again) to the fact you can easily restart a level when you think you messed up.
Those may seem to be details, but it's those kind of details that make a game easily playable and enjoyable or downright annoying.
The story is a nice little one (but that's not the main point of those puzzle games), the music and sounds effects are quite nice and not unnerving at all, the graphisms are cute, clear, precise (even the level the most hectic is never messy).
Well, it's hard to do a review when you have nothing negative to say or things you'd like to see improved ^^'
This game is fun, funny, and very entertaining !
If you like puzzles, do not hesitate !