UPDATE: Even a couple years after release, this is consistently one of the top indie puzzle games I ever recommend, even for people not completely enamored with that genre.

I've said this multiple times in my walkthrough videos for this game, but I still can't say it enough. This is one of the best executed indie puzzle games I've seen. It's simple without being dumbed down, complex enough without being confusing, and provides enough challenge to keep from being repetitive without being overly frustrating. I spent enough time in the game to get the full 999/999 but never felt like the game was a grind to do so. Definitely worth it.