It would be very fun to have RoR style progression through maps (with variation in enemies and terrain) through to an end boss. If you reset the curses on the between maps it might feel bad, as some of the fun of these types of games (imo) is getting a powerful build going and seeing how far you can push yourself (and the game engine). You could maybe have an "endless" mode, or a post-game map that goes on forever (after an end-boss or some such).
A lot to consider, but I think you could make a very fun full game out of this!