Nothing happens after I defeat Roy (on ZSNES 1.51), so unless I'm missing something, I can't get past World 1. If you address this and any other game-breaking bugs, though, this might have a chance of being accepted.
Also, the music breaks on Snes9x 1.53, which you might want to address in the future once music compatibility is more rigidly enforced.
Some other things I noticed as I was playing:
--Yoshi only has one frame of animation...?
--The item box flickers whenever an enemy gets hit, which is distracting.
--I think you're overusing piranha plants, as they've shown up in nearly every stage so far. If it's just a World 1 thing, that's fine, but it's going to get old fast if you continue to focus on them even later on.
--Roy has needlessly high HP, making the (Mouser) boss fight very repetitive and drawn-out.
--Your levels seem longer than they need to be. Mushroom Lake is the prime offender, with fish after fish after fish, but it's noticeable throughout the hack. I'd consider doing some cutting and revising, myself.
--Consider finding a proofreader or text helper, as the English in message boxes and such is rather messy.
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