He got quieter on some parts. Tell him to keep the same energy throughout the whole track. If he's not, either he needs to learn his lyrics better, or change the transition a bit.
He needs a little bit of more emotion. As an artist, he needs "Conviction"...I need to BELIEVE what you're saying. Either make the voice deeper or higher pitched. When he says "mic on my left hand, gun on my right" he needs to highlight "MIC on my LEFT hand, GUN on my RIGHT" etc...
If he can't, he needs to provide more word play to his punches to still be entertained, like Fabolous does.
Writing tip: Tell him to transition his rhyme into another rhyme, otherwise he will say a bunch of words without any rhymes and the audience might lose him.
I.e.
A,B
C,B
B, D
F, D
The B rhyme will go into D.
He did
A,B
C,B
D,E
F,E
Most of the time.
Check out Nicki's right through me
You let me win, (A) You let me ride (B)
You let me rock,(C) You let me slide (B)
And when they looking,(D) You let me hide (B)
Defend my honor, (F) Protect my pride (B)
The good advice, (B) I always hated (G)
But looking back , (H) It made me greater (G)
see how she went in on B, then before she switched to G, she used B again to transition to G.
don't ALWAYS do this, it will kill the flow. but i'm saying it, b/c it helps the flow a lot too.