This legitely give me strong jrpg vibe. Like I'm about to embark on a quest to save the world by activating the four elemental crystals, if you catch my drift haha~

I am sorry for what I am about to say, I am not at all a music expert nor someone who know any damn thing so i will use never-seen-before words to describe feeling and all but ... The moment when you have the main theme is really emotional, running along the chords (accord ? idk the right words, sry :/ ), and i really like these combinations (from 0:26 to 1:56, and the second one at 2.22 ). It give both a calm and nostalgic feeling, while somehow including the listener into the loop (like, it's open enough IMHO for one to link his/her/their tought to it, and emotionally relate, at the contrary, some other song "impose" a theme, with a more racy pace and all ... idk if that do make sense haha ^^'). It's also really catchy, has a lot of potential.

On the downside (well not really, again, i'm not a valid critic or anything, and it could be an artistic parti-pris that i am miss-interpretating, so, grain of salt, just my toughts and 2 cents on the matter), i feel like the very few seconds of intro "miss" something. I couldn't put my finger on still after 2 or 3 listens, ... But like, that slow part leave a void somehow and i'm just carving for something to happen. Like i said it could be design to let you feel that way, and i'm sorry, i wish i could communicate my tought way more easyly but ... In the meantime, just please know it's great and i'd like to ear moare. Haha~

The quiet/uncertain part is indeed on purpose. The character the theme is for is done sort of only partly corporeal being that came out of nowhere and decided to stay.
The into part is meant to give an uneasy feeling, while still not being really threatening, kind of like the character himself.