Harmony needs work, too much bass.
The strings harmonies don't fit very well with the piano melody. I suggest learning/working on counterpoint more. The strings either match the piano, making the song feel empty at such a low register, and there are a few points where the harmony doesn't match, and I'm not talking about nonharmonic tones. Follow your own chord structures.
And the other issue is that there is quite a lot of bass in this song, which means you're gonna need more of even lower bass to act as a foundation. In this case, a lot of melodic stuff is found in lower registers, so you have to be careful. Some parts of the song got dangerously close to being fuzzy sounding because there wasn't enough lower bass. An alternative is to focus on more chord work in the higher registers and keep the melody low.
Also, I know that you have your own intentions for each piece, but I find the piano very disappointing in this song, because all you do is use a single melody line. Pianos are very powerful and flexible, full, and unique because of how it's played. You have the potential for lots of accompaniment, chords, runs, counterpoints, etc, so use them and take advantage of them. For most songs, the piano parts themselves could almost act as a whole piece.
Piece does improve a bit when upper strings come in near the end, since it makes the piece feel more full and gives a solid foundation.
Though I do have to say, like most amateur works, this does have a lot of emotional effort put into it. For orchestral works with a lot of emotion, I do recommend suspended cymbals. They work wonders, with or without crashes at the end of them.
I would also recommend improving the chord progression by adding more variation and spicing it up a bit. Unfortunately, there's really no good way to describe this without going into a decent amount of music theory (not hard to learn though). I would at least recommend trying new things, especially outside of the box stuff.
For extra techniques to add flair, try ornaments, modulations (key changes, these are powerful), a few melodic fills, and slightly changing certain things in the piece as they repeat (this one is hard to describe, just experiment to see if you can improve on the original melody with more tension and just stick it on the end).
Hope this helps!
- stargroup100