I can't believe there are no comments here yet. This is a hidden gem. I've run dozens of Mausritter oneshots and this has been my favorite one. I've run it 5 times now for different groups, ranging from 3-5 players and from people new to RPGs altogether to Mausritter veterans. Everyone has loved it.
It has lots of different things to keep it interesting and allows for plenty of different approaches. The rooms are varied, making it a very fun adventure site to explore. It has multiple points of entry/exit and multiple different paths to take within. It features a larger puzzle that is very enjoyable, it's engaging but not too difficult. I've seen players solve it in different ways and I've seen a group take a different route and avoid it altogether. There are smaller puzzles and secrets to discover too, including various new spells. The NPCs fit the environment well. There is a "big bad" you could have a boss fight with, but it's not mandatory. Everything considered, this is a really good adventure that I strongly recommend to new players and veterans alike. If you're thinking about playing a Mausritter session, consider this adventure!