Is that a bad thing? Because I think they did that as well as possible (well, okay, maybe the only improvement they could have made is if they gave this game music in more franchises than just those by Nintendo, but then again, not too much that it lives up to its title as an “SMB1 Style Hack” any less).
Back in the 1990's there was an arcade machine that played Super Nintendo games. There was one in a big arcade on the Santa Monica Pier. The machine had Super Mario World , Super Ghouls & Ghosts, and a few others. Lately before the shutdown a Retro Arcade opened near where I live that has old video game arcade machines. When it first opened there was a help wanted sign for a manager and clerk. I thought it would be fun to buy one of those old arcade machines that had Super Nintendo games and stock it with Mario World hacks. The fun would be to observe customers select Super Mario World to play and then see one of the hacks come up for playing. I would really like to see customer's reactions. I can just hear "What the heck is this??? This isn't the Super Mario World I remember!" Then I could reply, " Of course not. You shifted into an alternate universe and the Super Mario World game is different from the universe you came from." Then they would be puzzled and say something like, " Alternate Universe?? What the heck are you talking about?"
This reminds me of that Sonic 3 style Sonic 2 hack where Soinc 2 plays like S3&K and the data select menu has the same music as the opinions menu, from vanilla Sonic 2. Also the stages/acts are connected and the screen don't transition to the next act.