Grabs you right away!
You are dumped in a place with no clue what's going on. Then you start exploring. The graphics are good, but what really got me was the excellent music and puzzles.
Some of the puzzles are very hard, and a couple of times I gave up and resorted to a walkthrough (I didn't try hard enough). That said, if you take your time, you should be able to figure out most of them yourself, as they are quite logical. The difficulty of the puzzles are well balances I think.
The puzzles was my favorite part. I could spend quite a long time, and then when I found the solution, I got a really good feeling and couldn't wait for the next one.
This came sucked me in right away. I found it so interesting and addictive I played it almost non-stop until I was done. Sat up all night.