Bug: The level complete music does not ever play.
Steps to reproduce:
1. Played every level of the game, very easy to reproduce on my end at least.

Environment:
JJ2 1.23 with JJ2+ 5.5. Running on Windows 7.

Do you have sound effects enabled? I think it's technically sound, not music. I just tried playing through Castle1 a few times, starting either from the episode select screen or from the command line, using both Jazz and Spaz, and the end sound played every time.

Can confirm the same happens to me. Occurs even when sound effects are enabled. Though, it's not that it never plays, but only the first few seconds of the level complete music plays then stops.

Happens on JJ2+ 5.6 and also JJ2 1.24 nonplus. Only happens in windowed mode, it plays completely in full screen.

https://www.youtube.com/watch?v=Po3sW3PGzss

Can also confirm. Same issue with the Sugar Rush music (sound), though I never figured out the circumstances in which it stops playing.

There's a good chance of the Sugar Rush sound to stop playing after destroying a skeleton.

The sugar rush sound bug is not caused by JJ2+ and most likely has a completely different source than the bug discussed in this thread. This issue will be considered closed when the level complete sound is restored. If you wish to discuss the sugar rush sound bug, please do so in a different thread.

Since the 5.12b update you can apparently restore the level complete sound in windowed mode by capping your FPS in the 50-90 range via /maxfps, something to consider?

Happens to me too, both the level complete bug and the skeleton sugar rush bug.