Hi, I enjoyed that. A few comments:
1) Bowing: can these instruments actually hold a note for 3 or 4 bars?
2) The cello is a bit monotonous, can you get it to wander more towards the top of the staff, and give it some melody to chew on? At the moment it's like a bored bear pacing its cage, and raising its head when a rare visitor throws a clandestine morsel of food at it. (if it makes sense...)
3) Not a big fan of the chord progression, bars 138-142 and 225-229.
4) It seemed to lose focus in the last third of the piece, but that may just be because I'm tired ;)