If it was a conscious choice, then all is well. Even found it very useful because I could estimate where I could stay in which shallow water despite the warning, as well as see the effects of an upgrade. To the music. Personally, I think that even if it only lasts 10 seconds, if it fits and is not annoying, then it's actually quite good. I fail at both points, so I use what already exists. The changes in the music are not actively noticeable, but neither do they have to be. ;)
PICO-8 is of course more difficult with less programming experience, but the game is very good for that and maybe you can share it in the Lexaloffle forum for more feedback and players. :)