I already adored Moss: Book 1, but Book 2 is sooo much better!
I expected just more content / new levels compared to Book 1, but the different weapons and skills take it to a whole new level. It's also rewarding to explore previous levels again, when you learned a new skill. And the game world seems to be around twice as big as Book 1 + its DLC.
The boss fights got bigger and better.