It definitely has potential this cover, but I have a couple of suggestion.
The stretched images has to be fixed, remember to hold down the shift key when you resize the images, that will keep the aspect ratio fixed.
To me the front looks a bit overcrowded, I would remove about half of the characters or at least 3 of them.
I think it would look good if the front was one color. I like the blue/green color the lower image got and I think it would look good if the top collage would look better in that color too. That would also bake the blending more seamless.
I'm personally not a fan of the old front banners, but if you do want to keep them I would suggest a blue/green color, cause I don't feel that sharp orange fits here.
I like that you have tried something different on the back. I would suggest you do a little rearrangement on the credit so you fill out that black area there is.
Of course it's all up to you (IMG:style_emoticons/default/8834.gif
My covers may only be viewed on well calibrated screens and printed on well calibrated printers.