Bro...Eminem could not only go toe to toe with Game but Game has taken way too many L's that Em could use against him.
The stripper story, Game on VladTV calling Recovery a classic and saying Em had him shook, Game losing that lawsuit, Game's latest album getting outsold by Em's compilation CD, Game having Ras Kass call him out for alleged ghostwriting, him Shang Tsunging other people's flows, Game's biggest songs featuring 50 Cent, etc.
That's too much ammo for Eminem to use against him in a rap battle.
And, mind you, I'm no stan or anything.
I'm just speaking facts. Even Game's diss track towards Em had him doing a good impersonation of him which can also be used as ammo against him. Em won't have much to worry about imho.