Eminem died in 2006/2007, drug OD. Interscope wasn't ready to let that cash cow go, so they found an impersonator. The reason we didn't see Em for a couple years was he was dead, and the impersonator was learning his mannerisms, voice, etc. Wonder why his face shows no emotion at all anymore and looks a lil different than before? The impersonator had a good deal of plastic surgery to look like Em, and it damaged a lot of the tissue. He can make angry expressions when he stretches his face yelling (like in concerts), but it's basically like people who get too much Botox. Wonder why he had the accent/is yelling? To disguise the fact it isn't really Em. The person doing his verses is very talented, but they have ghostwriters (explains the punchlines).
JK, just raising your blood pressure. It'd weird if all this turned out to be true though.