Samus' head looks a little too big when you look at it for too long, although it doesn't really take away from the picture being epic xD
The Rifle the ghost is holding looks like it was pulled really far back, but maybe that's just me.
I'm not trying to be picky, but I thought this might help you in the future.
Overall, the picture is great, the colouring is amazing... (O.O) positioning is great... just overall really good <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/>
Well, the computer is complaining that this critique is too short, so I guess I have to add this... Exactly100