It's a very tight precision platformer, the design is top notch and it feels great to play all the time.
It's just relatively short, especially for its price, but there's the whole time attack mode that I haven't touched a lot that can make the game last even longer -- you'll probably be done 100% of the game (minus time attack) in around 10 hours. More or less depending on your skill.
The game does a really great job of introducing new mechanics and stuff to avoid every level and fully using them so you get comfortable later on if you get the same obstacles. The levels are really well designed.