It would seem someone (check on TrueAchievements for their gamertag) managed to do this however, there's no timestamp for their achievement but so far it looks like a lot of their other games are legitimate. I just hope they didn't buckle under the pressure and decide to use a modding software to pop this achievement for a completion.
Someone did manage to beat 319 however, legitimately...but 320 is worse than that level.
The Evil Within (360)
Supernatural, Gotham, SOA
Current Top Shows:
The Strain, Hannibal, Arrow, The Walking Dead, Supernatural, Gotham