Bowser's Prison (Early Ver.) | B3313: The Beta/Lost/Unused Tracks
...I truly can't escape from this darn rabbit hole of a hack, can I? Sigh...anyways, I did a bit more digging and found some older dev builds of V1.0 that got leaked as well; specifically ones from March to early May (just an assumption). And of course, what is my primary interest when finding these? Looking for music not used in other versions, of course! Lol. Now, admittedly, this song in particular isn't a great example, since the only difference between this and the final version is literally the beginning portion. For some reason, the instruments change after the 30 seconds mark. Why? No clue. Likely was an error, tbh. Mostly because up until then, it was similar to the original version.
All credits belong to their proper owners. Thanks and enjoy the music!