I'm gonna let off a little here, but please remember this isn't personal - its about the track. This pretty much has everything which pisses me off about mashup makers. You've literally tempo matched the acapella to the instrumental and hit play. This has nothing to do with production at all, you're basically DJ'ing. Some of the notes sung are very clashy, the track hasn't been thought out at all, and to cap things off its distorting.
Even though the Psy track is a bit tired now, you had an opportunity to do something creative with it, and you went the (so very) easy route.
If you want to make mashups, great ... I love a good mashup. Just do it properly, don't become one of those idiots you see on Youtube whacking out a track because they made it in five minutes. That is not what mashups are about. People like that are killing what was an incredibly creative scene.
Like I said above this isn't designed to piss you off, I just hope you'll read this and think OK - lets do something about it.