The decision to shade so little of her hair and not to shade her shoes at all make those two parts of the picture seem flat. Her right hand (to the viewer's left) has seemingly random lines on it that I don't understand.
With respect to the background, I wonder if the logos would look better staggered, though I could potentially be off about this. In a simple grid, they look a bit repetitive and I wish a little staggering could have been done.
Overall the piece is nice, though the composition is a bit bland (standing straight, looking at viewer, legs apart). The colors mesh together well and the bright eye makes the piece come alive. That you chose pixel art as a medium is another kudos to you, as that's a time-consuming medium to choose.
On the deviantart community you'll find significantly more impressive works, which is the basis of my 3.5/5 (good, above average). Nonetheless, it's nice and well put-together.