The classic fire-flower would be nice.
I think this hack is really too hard to play it without savestates or rewinds. And I need to edit the first level of world 2. There are not even 2 shells,if there are two i could use a double-shelljump but so...
Not to beat,you should edit this. And I found every secret in world 1 so there isn't something which can help me. But the rest is good,also if it's very hard.