Just finished The Pirate Invasion! It took me 90 minutes, and I only got 58% secrets. And, I missed most of the cabins. :'(
This mansion is huge, unique, creative, delightful, and frustrating all in one. It had entirely too many hidden (and essential) keys for my taste. I also am not a fan of the signs warning the player against certain courses of action, as I feel it's bad design; you should be able to design your mansion such that not only are such signs unnecessary, but that, no matter what the player does, the mansion never becomes unfinishable. There were also at least two secret keys that were completely unreachable; I say that having fixed them for myself so I could get on with my life.
I also was looking forward to seeing everyone's cabin, but unfortunately for me, more than half of them were completely hidden, and I missed them. I wasn't in the mood to play the mansion over and over, never being guaranteed that I would ever find all the cabins. So...you fill in the rest. :-?
Overall, and notwithstanding the criticisms above, I really enjoyed TPI. Thanks to Brell for a good time!