Some cool things here, here's what I found in my nitpicking, lol, the cd to the right with the blue towards us looks a little flat because it doesn't appear to be showing a tilt properly, maybe this is to do with values or colour relations, I don't know. Also the female model looks like she has an ever so slightly flat right leg (underneath the knee, on the shin area), perhaps it's too much of one tone there? Again something about it seems lacking.
I've made these mistakes in drawing tons of times so that's how I noticed
Other than that these are pretty impressive and I would love to see some drawings of yours if they are around on this site somewhere.