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?