My honest opinion.
I really digg the happiness of the beat. I think the drums have a really great sound on them and they don't sound cheesy (like some hip-hop drums out there). Also loving the synths and everything else you have going on back there.
I'm a HUGE hip-hop fan and I love Tupac, but HONESTLY I feel like the vocals do not match up well with this beat. I feel like the beat would be nice just standing alone without the mashup. I know u were trying to go for a fusion of styles of hip hop and dnb (j-pop?) but I feel that this is something really hard to tackle and I'm not feelin it that much man. Sorry.
I'm not gonna vote you down since people seem to have a different opinion (114 downloads) but great job anyway though. Keep on tryin!