Hi! I think that's mostly all of them! The only other ending you might not have seen is where you collect all the cards. (We're working on an update to have them carry over from one save to the next but for now the drop rates are increased)
If you offer the cards to the statue at the end you will get the "secret ending" known as "Ascension"
Awesome! Got all the cards and beat the final boss as a pure human with slightly meatier features. I can safely report that curse level doesn't affect ending.
Edited my list to fix the endings. I assume there is an ending for beating the boss alone but I think I'll stick with saving Buttercup.
Enjoyed it just as much the second time through, probably top 3 TF games I've played though its a bit hard to find those. I know that job title changes as the curse progresses but have you considered changing Milly's name in the final state?
