I may have a bit of hearing loss, but it sounds like the left channel is a bit heavier than the right.
As a composition, this is wonderful, coherent, and pleasant to listen to! I may have some qualms with mix choice or instruments, particularly the bells, but other than that your talent and knowledge of music theory is clear to see. :)
I will dive now into nitpicking below.
First item of nitpicking -- overall volume. I think a free internet mastering service could be of great help here, or if you are not a fan, apply compression to your taste before you mix down your track. Audacity will also allow you to amplify an MP3 just under the point of damaging clipping, if you prefer no compression at all (and that's perfectly okay)
The piano is somewhat muffled in comparison to the ride bells coming in your intro. If you desire them to be that way, I would bring up the volume. I also think the leads through 1:06 are a bit loud. I would take them down by up to 1.3 dB. I hear an octave hiding underneath the lead around 36 seconds to 1:00 and on. Might be two octaves. You could either bring that out and pan it, or layer it in the same octave. I think it should sound better to bring it in on for a final chorus, where it is not hiding, as I can hear the lead cut off, and the accompaniment hold the same note for half a second longer.
The piece itself has great choices in instrumentation and arrangement. No complaints there. It manages to sound both classic, somehow Christmasy, and belonging to a cheery videogame/anime shopping scene at the same time. However it is quite mid heavy and low-mid heavy on the mix, leading to a boxy sound. I want to hear some more of that 8k-18k!
I think close to the outro, the high bass clashes somewhat with the rest of the arrangement 1:45
You could bring that bass down there, or bring it down one octave. One thing I notice, the bass seems to have some formant shifting going on, as well as a delay, and sounds very, very soft on the attack -- is that a frequency comb or bit crush that I'm hearing? I think those would sound much nicer without any delay or reverb of any kind, to just let your bass unapologetically be itself. You want as little noise muddying those low frequencies as possible, or each time you hop to another note, you're going to get clashing frequencies.
All the considerations I mentioned above would bring the bottom end more to the forefront and vary the timbre more. You may also try bringing the sub down in volume. I notice that also is quite loud relative to the "head" of the bass, and it makes the rest of the track sound out of balance. To get more presence out of a bass you can experiment with distortion/amps.
Your percussion could use a bit of a facelift with some light transient shaping -- kick/snare. The cymbals would benefit from playing with width. You may also play with humanization on those velocities a bit more and thin out the lower mid range on what seems to be functioning as a ride cymbal at 1:28. It's quite loud relative to the bells you have going on. Personally I would take it down and crescendo all the way through 1:59, maybe with slow motion panning around, because motion is everything.
The bells on this section, while adding Christmas spirit, are muddying into each other, making individual rhythms on the same key hard to hear. Playing with accents, reducing reverb and reverb length, and decluttering the piano roll of multiple notes can help with that. You may also take the harmony you want and move it to a separate instance of the instrument with slightly different panning. I use this trick frequently.
I think your crashes could actually use long reverb tails and the occasional reverse crash leading up to them for transitions. I'm super fond of that and think it would work wonders for the big transitions in your piece to make them more dramatic.
As I listen more and more, I start to focus on your kick. I'm not sure if you designed it yourself -- have you considered tuning your kick to the tonic of your track, and tuning the sub? You can accomplish the first with a simple guitar tuner plugin and the pitch wheel of your sampler, if used. Following that, KSHMR Essentials Kick would be a nice quick fix to choose a sub note, fix transients, widen, etc, to your liking. It seems boxy in the 250 hz range to me.
The snare by itself does not sound bad but seems to be having issues cutting through. A little more processing would probably do the trick, focusing on transient shaping, saturation, bit crush, width, clipping... You may also think to tune your snare accordingly.
Overall, it's a great listen, a very whimsical, fun piece to sift through. I really enjoyed it.
Thanks for coming out to NGUAC!