I find DragonNightWolf's piece I bit too incoherent (opinion)
Marcuz Larkz's piece could use a little more value contrast, and work with shape and space. perhaps look at that arm a little more it feels too awkward
in afb728's piece the concept is wonderful (im a huge df fan) I really enjoy the rough line work of this piece and think it adds to the aesthetics of the piece, though at times the lines maybe lost in this rough line work such as the headphone wires. Were I believe this piece lacks though is the use of negative space; there is no use of negative space. If something were done with your negative space it could really turn this piece around.
Rander's piece is fantastically illustrated, great shading and use of space. but perhaps a better rendering of the human body would help as the subjects' bodies appear awkwardly, especially the female's hand.
finally Bruextian's piece, a great use of shape, form, space, shadow, texture, and linework! a little more attention to the bottom of the tv monitor (the button area), the speaker in the back, and the aliens eyes, could be used/rendered better. Also the value contrast could be pushed more to make your image really pop; truer blacks/shadows, and highlights. but as-is the piece is still very well crafted.
~thankYou to every one who entered, you all have very amazing pieces, and cant wait to see more from you!