you, me and Dave C, so far, have noticed that some games have had this happen, with the music slowing down. I forget what game it was I noticed this on now... maybe Ghouls and Ghosts? I forget I was kinda in a rush. Dave C noticed it in Thunderforce 3.
As far as the sound not sounding right in SoR 2, you probably had it set on the default sound quality (8000-whatever it is), in which case it will sound a bit off from what you probably remember it. Reesy mentions in the readme that the default sound quality of the older betas was the 16000 whatever it was setting, so if you change it to that setting in Beta 7 it will sound fine.
As far as the sound not sounding right in SoR 2, you probably had it set on the default sound quality (8000-whatever it is), in which case it will sound a bit off from what you probably remember it. Reesy mentions in the readme that the default sound quality of the older betas was the 16000 whatever it was setting, so if you change it to that setting in Beta 7 it will sound fine.