Psychonauts was criticized a bit when it came out, but it's stature is starting to grow. I see it mentioned in articles from time to time about little games that are great (and now cheap), and the original criticisms seem to be waning. It's become a bit of a cult classic in gaming which isn't surprising since it's from the creator of Grim Fandango. It's $10 for the full game now if you can find it.