After playing through all the games for voting, I realized some flaws in your game, but only if you run it on a classic Game Boy (DMG). The battlescreen gets completely black, except the enemy. The bag is black. The professor glitches (black) in the first scene. You get some textbox glitches and my actor got invisible after spending all my money in the shop.
You should consider, blocking the game completely from being started on a DMG.
On Game Boy Color this is absolutely fantastic though. But I don't really get the save game system. :D
The music player setup is cool. The basic concept works fine. And you put tons of content in the game, which is totally crazy. :)