Ok, so I'm listening to v4 at half-system volume and headphones that came with my Samsung Galaxy Player, an I notice that the percussion at :22 is really powerful in the upper frequency range, like 8k o 14k. It's almost painful, and I'm listening at half-volume.
(Then again, I usually have Windows Media Player at half-volume o less to prevent hearing damage, I get enough of that in percussion class. I'm listening to your mix through Chrome's built-in audio player at 100% player, 50% master volume)
I think the bitcrush is a bit much on the opening bells.
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One thing I notice throughout the song is that you seem to expand your sound in one direction: higher and higher in frequency.
Don't be afraid to filter parts even if it's only slightly. You might want to use a spectrameter (or whatever it's called) and check for spikes while mixing.
Other than this, I don't really have any complaints. (ahaha bullshit oxymoron, but whatever)
Oh, one more thing, if you really want, you can humanize your track a bit more, even if it's as simple as randomizing velocities by 10% or something like that. Maybe offset some notes. Whatever, it's all up to you