Hi Awsumerguy,
Pretty much has been said by our peers here, and my criticism is still primarily about your violin writing. My sister plays the violin, so I know a little bit about writing for the violin and may be able to give you some insight:
Notes in downbeats (especially if they begin a phrase) and accented notes or chords are usually played with the down-bow stroke. For example, in bar 104, the B-flats should be down-bowed instead of up-bowed. The same goes for bar 127: while you mentioned con forza in the violin part, it is recommended that the accented B-flat be down-bowed.
Some triple and quadruple stops may be unplayable, as mentioned by PCC and Henry. For example, the chord in bar 209 may not be practical to play because it would require the fingers to be placed awkwardly on the fingerboard. Also, the F major chord in bar 175 is utterly unplayable because the middle C cannot be played on the D string.
Like what PCC mentioned, there are very few slurs in the violin part. Notes under a slur are played in a single bow stroke, and I suggest you use it for expressiveness when writing for the violin. For example, consider applying it on the sixteenth-note runs in bars 127-128.
When writing for a musical instrument, it is crucial to understand its limitations and common usage, such as keys. For example, musical keys such as G, D, A, and E major are well-suited for the violin because they are based on the instrument's standard tuning (G, D, A, and E). While playing pieces in A-flat major on the violin is possible, its usage is limited because the A-flat major scale contains very few open string notes: only G. Therefore, this makes flat keys most suitable for slow and expressive pieces that involve the violin.
I am pretty confused about bars 19-20, 105-106, 116-117, and similar passages in the violin part. While it is a tie, both notes are played on different strokes, making them sound separate. I am not sure how violinists would play these passages.
Lastly, as PCC said, the E-flat in bar 19 cannot be played as a natural harmonic. Although harmonics are a great way to change the instrument's timbre, it is essential to research playing harmonics on the violin, which includes natural and artificial harmonics. For example, the harmonics that can be naturally played on the E string (fundamental note: E4) are E5, B5, E6, G#6, B6, and so on (notes are named according to the scientific pitch notation).
This pretty much summarizes what our peers have said. Anyway, thank you for sharing this piece!
Carl Koh Wei Hao
P.S. By the way, A-flat major is one of my favourite keys!