Some critiques:
The ESRB logo does not fully cover the one on the original cover, and the top and bottom edges of the front are cropped off, and the left side of the back, try to make the left border equal to the right.
And the colors could be a bit brighter, compare the wight on the THQ logo to the White on the ESRB. Maybe sharpen it a bit too.
Also the game box does not have the ONLY FOR logo on the front.
On the 3DS covet, the BG of the spine overlaps the back a bit.
2 good techniques for cover making:
When working with black text on a white BG, or anything without color, desaturate it, and mess with the contrast and brightness. It's a good way to fix up Bar codes, among other things.
If you want to make a solid color, for the spine or whatever, and you want to make it match with a scan with some moire, the pattern tool in Photoshop is a good way to make it, just sample an area of the scan with a flat color.
Here is my cover with the 300DPI scans for reference on the colors.
