More flaws for you guys to correct:
The last part of World 2-3 (the goal), the dark area, is supposed to play the ground-level music (as usual), despite the graphics there looking like underground. Looks like there's more code you should do in your expansion to meet this demand.
Also: In the coin bonus rooms in Worlds 1-4 and 2-2, Mario is supposed to drop down from the top. Additionally, when he exits the coin bonus room of 2-2, he is supposed to emerge from the topmost pipe upon returning to the water level.
The bonus pipe in World 4-3's sky bonus (underground graphics)... I cannot go down it.