Main Menu: feels very Fire Emblem circa-2002 on Gamebody Advance. Even a bit of Final Fantasy energy! I will say, this does fall into the trap of looping chords. I suggest adding a little more material, like a B section, to break up the repetition--or make the repetition a bit longer, add a key change, etc. etc. Still, it's a super-solid track with a distinct vibe. It sets up the rest of the soundtrack well.
Overworld Exploration: again, the track is a bit repetitive, which can be a bit difficult to battle when using a drone. There is some more contrasting material in the strings, which I like (especially when layered with the existing melody!) However, because the same melody repeats so much, it doesn't feel like there's much of a sense of progression. Adding more instruments does increase the intensity of the track, but I might suggest adding more texture instead of doubling the melody. Consider adding more notes to the drone, some strings, percussion accompanying, etc.
Overworld Combat: Love the stabbing strings and intense dissonance--this is a really exciting, edge-of-your-seat track at the start. However, there's then a repeat of the same material four times, with very little variety. It's a much more relaxed vibe than I expected for combat music. The beginning and ending are both my favorites--very inventive, unafraid and dramatic, with flair. I would have loved more of that throughout the piece!
Aethelgard: Another real banger--loving the use of mixed meter, the striking strings, aggressive percussion, string runs, etc. used in this one. It's another one where there are longer repeating sections. Without much changing, it may have even been better to condense these sections to one or two repeats? It's okay to have shorter tracks with less repeats. If this track was half as long, it would have been just as effective, if not more.
Closing credits: I'm sorry if I sound like a broken record player here, but again, there's just a bit too much repetition for my taste. When the shaker and flute comes in with a tempo change, I loved the switch-up and this new vibe. Don't linger too long on one idea, because it does take away from the enjoyment!
I'm sorry if I came off as harsh here: the truth is, you have a lot of promise and a strong foundation to build on. Next time, try to let your mind wander more: how do I extend this short melody into a longer one? Can I change the chords, instrumentation, melody, etc. to lengthen a musical idea instead of just adding to it while repeating it? Good work, and keep writing!