I remember hearing these tracks in the game, and they fit with the progressive story element well. It's hard to tell what some of these themes are specifically for (characters, areas, situations), but they seem to share a similar mood (I get sort of a Stranger Things vibe). I wasn't prepared to hear any vocals, so that was a nice surprise. Everything has a good sense of rhythm and driving percussion.
The sound quality, mixing, and dynamics make it seem to me like you know what you're doing as a composer (unlike me haha). I don't know what software you use, but it seems to be working out well. Are you the only composer or did you get help? Are those your vocals, someone else's, or are they just samples?
Do you know what leitmotif is? Lots of good composers use it to hide little messages and hints in their music, and I use it extensively in my OST. I heard some of it kind of touched on, with the main bongo-like sound in the battle theme. I heard it pop back up in a few other tracks... coincidence, or something more?
Here's Grass Elemental's OST (for now): https://grasselementalost.bandcamp.com/album/grass-elemental-demo-demo-ost
Though most of this is Gameboy music, the majority of the finished OST will not be chiptune. I am not an experienced composer at all, and this is my first soundtrack, so I hope it isn't too rough lol.