I often miss certain information in reviews. Therefore I post it here for people like me, who need it quick and easy.

Playtime: ~20 hrs.
Levels: 34 – from small to big - beautiful and surreal – arena-like
Backtracking between levels: yes
Secrets: yes
Achievements: no
Unlockables: few
Collectables: stars for finding everything
Replayability: 3 times at least
Sense of wonder: massive