The most I will tell you is that it's an adventure game with some minor tower defense elements. And that it is the best game I've ever played, and no game has ever topped it since.
I've recently been eyeing the case for that game on the shelf and thinking about going back to it, but it's been so long since I last played that I 100% would need to start over again. I had gotten prob 20+ hours so it's a lot to lose. But I remember the story being pretty mindbending, and there being some interesting mechanics.