I believe this game should be shown to all psychotherapists so they can prescript it to people with anxiety or stress issues. It's extremely relaxing and serening.
Beautiful, minimalist atmospheres. With an abstract yet catching story and mysterious aura around it. Gameplay mechanics are fluid, sharp, accurate and the character always seems to be involving with its environment merrily.
Difficulty level is just right (for me). Puzzles are simple and it's always natural to figure out what to do first.
...Can't wait for a sequel or a (more complex) spin-off. Maybe more worlds? Maybe more characters? It doesn't need any violence, by the way. I enjoy it just like how it currently is: nice and peaceful.