Ca. 8 minutes for String Quartet

A String Quartet Project I'm working on. This is an initial sketch of ideas up to two minues and will eventually be up to 8 minutes. I'd love to get feedback from anyone who knows more about composition that I do. Do you think this shows promise?

Ca. 8 minutes for String Quartet

It doesn't sound too bad, nice sense of tension and release, aesthetically tight and coherent. My one complaint is monotony. Have you studied counterpoint much yet? There's a lot of themes in here that can use or be exposed to contrapuntal variation, such as the part at 1:40 on; rather than just having the cellos double what the other instruments do, a countermelody of some sort would help bring more depth into it. String quartets are one of the hardest pieces to compose because the instruments are all pretty identical timbres, so counterpoint is your friend in writing them.