~=Updated to reflect the official release=~
* Straightfoward gameplay;
* Appealing to all ages;
* Well polished;
* Colorful graphics;
* Good soundtrack;
* Easy cheevos for achievement hunters;
* Enough content to justify the price (the level editor is awesome!).
Mousecraft is a delightful casual experience. The puzzles are straighforward, but propose a nice, non-frustrating challenge should you decide to get a "Perfect" rating.
I think the game finds a nice balance in its audience as it can appeal to both the young and the "old." From personal experience, teenagers and overall competitive people will not enjoy the game very much as it is not fast paced and does not rely on skill, but rather your ability to analyze a situation and consider all the elements that are part of it. It does have leaderboards, but the scoring system is a bit obscure, making competition somewhat pointless.
To me, it is a perfect game to play after a stressful day to unwind. It is colorful, cute, and the cat scientist on the background, Schrödinger, always makes me smile with his reactions to the things you do. So, even if you fail a puzzle, it is still fun to watch him react to it -- you don't feel like you're losing, but that you should try better next time.
I'd also recommend this game to achievement hunters: it is very easy to get all the achievements; the second quickest I ever played. So even if you're not into puzzles, it should be simple to get it to 100% (especially with all the guides already available) and crank up your achievement percentage up a bit. Plus you'll be supporting a really cool indie developer -- they're awesome, hard-working people that have a lot of creativity and good ideas to share.
I've followed this project for quite a long time while it was in development, and I must say they did quite a good job, especially for being their first game. The quality is impressive, and the amount of polish shows they're really enjoying what they are doing. That alone makes them deserve our support. Crunching Koalas is an innovative indie game developer that brings that much-needed breath of fresh air to our gaming community, and I am looking forward to many other great games they might create.