Thanks for your feedback, and I'm glad to hear you liked the music and art style. (even if it was apparently too loud for you)
The music being too loud was something I was concerned about, but not something I can easily adjust as everyone's audio settings are different. I would probably have to add some sort of volume option or a way to toggle the music. The other track you heard supposed to be ambient track, but it wasn't noticeable when played with the overworld theme, so currently they alternate between the two since as I felt that the overworld theme nonstop would get tiresome eventually. (Though a secret music track would have been a great idea)
I completely understand having a hard time keeping up with combat, and attack animations was something that I had wanted to do, but had put off since I knew there was no way I could get them done in time. I think I'll also add some sort of message as you suggested as well.
When initially planning the game I wanted to make sure the player didn't have to wait too long during combat, but it seems it's still too fast for people. There is actually something of an indicator in the game currently, as when a monster takes damage, the amount of damage appears on the screen briefly, but it's probably hard to notice if you don't know what you're looking for.