This my second Muckenhoupt game after Gostak, and I found it compelling. You have an evil twin who is always out to get you, and you him. You go out to try and stop him from hurting others.
There is another world out there, his world, a mirror world of evil. The main mechanic of the game is travelling between the worlds and using their transformative properties.
The plot has a few surprises to pull out, and their are some tricky (but no too tricky) puzzles.
I love this game, but I'm a big fan of dual-world games.