Hard to see the character and the bright lights in the top right are extremely distracting, maybe die it down like you did to the blue in the bottom right... i still can not see the render's arm at all in this image...
Looks great I agree that the colors could use some working on. If you can adding a sense of texture to the body would be great too. Other than that there ins't much to fix but I feel that the sig might be too big lol...
The bottom of the sig is like you really cutted his legs. That part should be solved if you know what I mean.
Also MAYBE popping out the render a bit might be an option, but as it is, it integrats prefectly with the background.
Overall 9.5/10 (fix legs and 10/10)
Formerly known as gamer4evere
MPGH GAMING NIGHT 08/03/2015 - Town of Salem