Not really a game idea but I like this kind of puzzle games:

I just started playing 'Mind: Path to Thalamus'.

In the beginning it was quite interesting, but after playing some minutes the environments and leveldesign just blew me away...
The Ideas (leveldesign aswell as gameplay) are interesting and it looks imo. much better that most AAA titles, even without any advanced rendering techniques:


From what I've seen the puzzles are really cool so far and the music is great, aswell.
Probably worth giving a try