Can you critique my UTAU song mixing??

Ryuuoh DeltaPlus

Teto's Territory
Defender of Defoko
Good day guys!

I was wondering how am I faring with my song mixing skills, so I'm here to make you critique my work. I also appreciate if you give me tips on how to make my mixing skills better. (BTW, I'm using Adobe Audition CS5 to make this).

[soundcloud]https://soundcloud.com/gatxx03/ryan-moriyama-feat-hajime[/soundcloud]

Thanks for your opinions!!

PS. My friend said that I need to equalize the volume in this sample. I really can't understand what she meant. It will help me guys if you can explaing why she said that.