The Game just got a little more Iron in his diet -- getting Mike Tyson's face tattooed on his fist.

Besides being a huge Tyson fan, Game also has penchant for punching people ... including another rapper named 40 Glocc ... and mentioned that street fight in a post after getting the new ink.

"Now when the judge ask me in court if I whooped 40 glock ass I can truthfully say no & blame it on @MikeTyson .... My right hand man lol."

And of course, he added the proper hashtag -- #MikeTysonPunchOut.