Between casual and hardcore...
In a word, you need to reach from point A to B using Goos - animate ball-like creatures. Pretty simple task huh, and funny because of Goos being cheerful and diverse, each one with own abilities and own 'way to be used' that needs to be figured out.
The story is somewhat blurred, but is able to arise some interest and does not feel to be rudimentary.
The graphics are cartoony and pleasant, could be better but it's just enough to love the Goos :)
All who is not indifferent to puzzle games (and also the ones that think they are), don't pass by. Of course this is not Portal, but the game is great in his own way...