TheNiceGuy, Hagashi, and Ronthis: Could you all be more constructive in your box criticism instead of user criticism? Everyone has to start somewhere, and comments like that surely won't help.
As for the box itself, if he is indeed 13 I would recommend him to definitely make his own account. The front has a good foundation, and the halftone isn't bad, but you could do a better job of representing the game by using environments. Having the characters floating is also something you want to keep from doing, as it makes the design look much less professional. As for the back, I would say ditch the angled screenshots and text and go for a more streamlined and clean look. Again, using some in-game assets or other game images could help.
I was just saying you and your brother should work together from now own, making new boxes, like teamwork or something.
And I still think your bro's idea of using a halftone background was a good thing, it's not a plain background for beginning with. The presentation is going fine, I just would change the renders from the front to not give the idea of them being "floating in the air". Also, just leave Sonic, because Tails and Knuckles are not in the game.