Beautiful piano intro. Like the key change at 0:22.
Second part nicely builds upon the motiff established in the intro, though the pads may be a bit loud... they kind of compete with the piano around 1:10 (also, IMO the piano phrase at 1:08 would've been a good opportunity for a dramatic crescendo). Nice tension and resolution into another key around 1:19.
Third section has a fun sneaking around vibe. I like the call and response between the bass and piano. Mallets and strings provide tension, particularly the dissonance around 2:50. The percussion coming in at 3:34 is a dramatic moment and immediately lends urgency to the piece. I like the broken up variation of the main motiff around 3:49. Very interesting, unexpected pitch modulation at 4:06.
Ending section is a nice callback to the second section with added percussion. Works well. Good job, a very enjoyable piece! If I were to take issue with anything, it would be that the song changed from one section to the next with little/no transition. Yes, it's an overture, but a transitional phrase or measure would've gone a long way towards leading the listener to the next part. Alternatively, breaking the song into separate songs would've worked well.