You definitely have an original style and I do like it a lot :) The thing I'd like to point out is shading.. Try using an airbrush tool to add in lighting and shadows to give it more of a 3D effect. Since I am not familiar with Photoshop or box art(I am a mangaka) I can't help too much ^-^'
All I can say is be original and practice lots ^-^ If you need to, use lots of references but ALWAYS credit the original artist or it is considered art theft! If you are in desperate need of inspiration, here is a link to my deviantart page XD I am also not very good yet but I love helping :3 http://rosemink.deviantart.com/
I would not like to offend you as I have only been drawing for a year, but that is near god awful.. And the music was also not very good. Try coming up with original stuff and not be an art thief. Too many have stolen my art before, and I hate seeing art thieves try to become popular off of somebody else's work..