Tip: Switch palace switches normally disappear if you replay the level. However, if you insert them as direct Map16 and use the hex edit at $00EEB2 in the ROM map, you can replay the level without a problem.
Updated the download with a version that fixes the bug with Naval Piranha possibly softlocking the game. This also partially fixes the 1-4 bug in that items do not normally duplicate. However, there is still an issue in that it is possible for a flower in the first battle room to turn into another tulip if you leave the room. Leaving and returning again appears to fix this.
Some excellent levels, and of course some garbage, but overall was pretty cool!
I don't think it was supposed to end during the "island" cutscene after completing the 4th world, but when Yoshi started glowing, to presumably teleport to
world 5 my game went completely black, I can't proceed any farther after the Koopa boss.
EDIT: tested this again, using a savestate that I made earlier in the game, still happened.
Also, if I reset the emulator after the black screen happens, it just shows the Nintendo Presents screen over and over until eventually crashing my emulator.
I'm using SNES9x by the way.
Oof, that's a pretty big issue. It's been a while since the last time we tested the hack front to back, so we must have missed this one. We'll try to fix this as soon as we can. In the mean time, please make a backup of your save file. Here's a 100% save you can use to continue playing the hack: YI 100% SAVE
Ignore the levels in world 6, they don't work.