Close; but no cigar.
I do give you credit for making this theme better than what it originally was, and infact, I wish this theme was actually used in Devil May Cry 4. While most people's voices are different, and others are very unique (like McPherson's), I do feel that McPherson would write more smooth and eloquent, and not so obvious as some of your lyrics are here. (I mean, a few of your lines actually sound like something I'd expect from a rap song, and I don't want to hear rap crap.)
Either way, you put great effort into this, and considering how good you performed, I do give you the following ruling
The score may be perfect; but if it was done like Shawn McPherson himself, I'd give it a little more. :)