Why is this video the first time my music has ever appeared in an animated project without me having a hand in it lmao

It’s pretty damn good, but would be even better if it was longer.

Honestly feels more like 128bpm rather than 256bpm. Still great though!

It's pretty good, although I don't think a lot of the loops you're using really match that well.

The beginning is good, because of the piano parts. The audience get this feeling of inspiration. It sounds like a couple running along the beach, or a bunch of foxes running through the plains.
Then you get this octave-patterned disco bass, which is usually supposed to be used in more electronic music.
Also why is there a super-loud suspense sound effect at 1:10? There's been nothing suspenseful about this song at all until now. Maybe make it a lot quieter so it's less of a major aspect of the song.
Then after the suspense sound effect you get... rock music. A strange decision, to be honest. Sometimes using rock guitars in a song like this is a good idea, if you use it for rhythm. Make it a secondary aspect of the song. But you don't really do that. Instead you just introduce a whole new tune, melody and beat, and it clashes with the piano loops you already have.

You have a long, long way to go. How I'd improve your style is to be more fussy and picky about your instrument selections. Ask yourself "this sounds good, but does it fit with what I already have, or would it be more fitting in a completely different song?". Also, please don't just use premade loops. That's just lazy. I believe you can make really good music if you put a little more T&C into your work and spend a little longer than just an hour on your projects.