By Jackson Stein, Staff Writer [Shady; 2020] Rating: 5.5/10 Key tracks: “Darkness”, “Yah Yah”, “Lock It Up” If Eminem dropped a surprise record 20 years ago, listeners across the world would scramble to their nearest record store, needing to hear what the Detroit rap legend had to say. After all, Eminem was hip-hop’s brilliantly diabolical…