A demo real soon you say? Maybe someone hook old DELTA here up. jk

Anyway, it looks pretty good for a 2D sketch. The very top of the helmet needs to be just a little less bulbess. The biohazard sign on the torso definitely needs to go. Other than that, you should ask for feedback again once you have a 3D WIP.

EDIT- and the neck needs to be a bit thicker where it meets with the helmet.