I think the intro is a bit jarring with the strings punching the left ear pretty hard. Centralizing the panning a bit and widening them out would help balance that for sure, as the left ear is getting too much information whereas the right gets essentially none.
Welcome to Your Inner City is really groovy and a jam! I enjoy the soundfont choices and melody a lot. It also sounds like the bass is panned to the left throughout a good chunk of the song, and I would advise to keep that pretty centralized to keep the mix balanced.
Bustling Brain is another jam! Feels very fresh and ear wormy. I think you did pretty well with the production on this one.
In Angry Denizens of the Big Watermelon, I think the hard left panning on a few instruments obscures them too much and has them fighting for attention. The composition itself is great though and also a banger.
Battle Against a Traumatic Opponent is such an Earthbound title and I love that. The piece is super high energy and realllly catchy, but the mix does feel kinda off kilter at times when things get really hectic.
I think Let Go is really goofy and fun, but the bass is a bit muddy when it goes super low.
I loved your entry a lot and I thought it was super fun and creative, and definitely was able to pick up on all the Undertale influence. My biggest gripe is some of the mixing choices, but your compositions were pretty on point!