Very nice overall
I like this piece very much, it's not too "flashy" and well detailed.
For only two hours, this is great. I couldn't do something like that in two days! ;)
Well, I have one tiny bit of criticism though, the upper portion of the lower part of where you lay the body of the banjo (no idea how else to describe it) seems kind of twisted out of perspective, in comparison to the other aspect...
Still, I like this drawing very much.