Well like I said this new game is mainly a graphics update, not much will be different except a few changes here and there, a few surprises added, or some things that people complained about taken off (enemies always return, less windrobes on later levels).
However, I did note from the original game the bosses were kinda easy so this time they should be somewhat harder; that hopefully balances with the enemies don't return, I don't want to make the game too easy either..
