This is pretty damn cool. This hack is super visually impressive, I really liked the little story at the start and how Mario actually falls into the overworld. I do have a few issues though, like the Hammer Suit is super janky. It's very commendable that you tried to make it from scratch but it needs a lot of work, I'd suggest LX5's power-up package to cut out a lot of work. I did really like the other hammer power-up from 1-1, that was fun little level gimmick and I liked how you can use other power-ups with it (although shouldn't those cracked hard blocks be destroyed by the hammer instead of a shell?
). It does share an issue with the hammer suit in that the level design doesn't really put it to good use. I couldn't hit shit in 9-4 with the hammers and with the other hammer I never went "wow I sure am glad I have this hammer", basically just try to think about enemy placements more and how they work with all forms of Mario and maybe some secret paths requiring certain power-ups would be cool. By the way, in 9-4 those 1 block pools of lava are a little too harmless looking and I got hit thinking they were decoration, then I was afraid of the little lava falls and they're just decoration. I'd say try to make them more distinct and harmful. Besides my few gripes this is fuckin' awesome and I'm super excited to see this progress, good luck dude!
Swing God gun, I need it low demon