I played the hack in Snes9x, beacuse I only use ZSNES when playing old hacks.
Is the title screen's layout and text taken from Link13's SMB3 style hack?
When a message box appear, both the HDMA and layer 3 disappear. The messages are also blank for some reason. I can't look in LM because you locked the hack.
This happens with most levels.
The yellow ! block doesn't have the same colors as the ? blocks.
In levels without layer 3 and HDMA, such as castles and switch palaces, the message is readable, but has a bad palette.
When completing a level after layer 3 disappeared, it reappears.
The clouds went over the waterfall background when completing this level.
The goal sign has a bad palette.
Also I would change the grassland foreground graphics, because it looks like SMW's graphics.