Staticm40 RH: This arpeggio marking is at a slight angle for some reason.
Oops must've clicked something I shouldn't have
m55/71 RH: Beat 2 should be An instead of Ab, and I think the grace note is just from the echo and not actually a note.
Yeah I agree that it's an An but I doubt it's an echo, it's enunciated way more than the background echos. Changed the note though
m79 RH: I would suggest including the Eb in here from the choir part, both to show its resolution to D in m80, but also to give a taste of that augmented harmony in m79.
That's probably a good idea. I also added some voice leading in the measures around it and separated the layers to show the movement
Maybe include a D.C. or repeat, since the track repeats in-game.
Hmm yeah the soundtrack doesn't loop, but it wouldn't hurt to tell the player where the repeat goes. Added a D.C. to the end
Latiospp and mp seem a bit soft for the song? It's subdued but doesn't feel that subdued, to me at least. Up to you though 
I had another listen over the whole song and changed the dynamics placement a bit. It starts at
p now and climaxes with mf at m81, whereas before the loudest point was
mp at m33 which definitely didn't sound like the most energetic place in the original
I think the octaves in the LH in m. 4/8/12 make it sound a bit heavy. How about removing the lower G?
Yeah I agree, took out the octave
The LH in m. 32 sounds a bit weird with open fifths - you get exposed tritones on beats 2-3. I think making these triads (adding the third) would sound better. Same goes for m. 48, what do you think?
Oh yeah I didn't notice those 3rds in there. Made them into triads
I'm not sure I understand the reasoning for putting slurs specifically in the places you have them, but it's up to you.
I don't think I did a very good job with the slurs in general, so I did another pass and leaned more into phrasing than legato for the placement. Hopefully it's better now
For the slur in m. 19/35, is this supposed to convey the existence of the bottom layer? It seems a bit odd to have it bend from the Bb to the C. I think I'd suggest writing these couple measures similar to how 27 is written
Took this advice nugget
You could use a slur on the single notes in m. 84-85 to signal they're part of a different phrase.
I think those notes are clearer now that the other phrases are marked with slurs. I still want them to be staccato to indicate lightness, so I'm hesitant to add a slur and make them look tenuto
Along similar lines, the upper LH notes on top of beat 1 of m. 77 and 79 strike me as a bit odd, obscuring the bass note strike. Could they be included as RH harmony instead?
I originally lowered the entire harmony in that section by an octave since the melody leaps down in m78, so otherwise the harmony would obscure the melody instead of the bass there. But you're right about it sounding a bit muddy, so I think it sounds fine to just leave the harmony in the upper register and omit the D from m78 specifically. I still included the second D above the melody in m80 because that m79 Eb in G major wants really badly to resolve to D
I'm definitely hearing this as Gav wrote it but with the grace note being An instead of Ab.
I'm listening again and I hear the An pretty clearly right on beat 2 of both of these measures. The Bb only plays on beat 1, and there is no grace note (it's just an echo). It's easier to tell when it's slowed down (like 0.75x).
Yeah I still think it's not an echo too. You can hear the delay effect on the Bb from beat 1 there and it sounds much different than the An. There's also not an An played anywhere beforehand that could've caused an echo. Still agree about changing it to An though
Also added an upper C to the RH on m87 beat 1. I'm not totally convinced that it's a piano note and not from the glockenspiel, but there isn't a C in that measure until beat 3 to complete the AbM7 so I added it