the Covenant symbol on his/her/its tank looks a bit off, maybe because it is exactly vertical while the whole tank is a bit sloped. I think if you turn it maybe 30 degrees counter-clockwise and hid a bit of it behind the hand, it won't look as odd to me.

Another think I noticed is that the Plasma Pistol appears to be behind his/her/its hand, instead of in his/her/its clutch. I have absolutely no idea how to fix that impression for me, but it doesn't hamper your design at all, so might as well keep it as it is.