"Down at the Half" is awarded for beating the second volume of the "Gunslinger Joe" Freedom Chronicle DLC. This section of the DLC begins with
*** Spoiler - click to reveal ***a faux nightmare football field fight against a lot of Nazi's and some Klansmen enemies with limited resources. There's two ways out during this bit, die or "beat" the dream.
You should also still being playing on Mein Leben or a harder difficulty like "I am death incarnate," so as to work your way towards or practice for the "All-Pro Warrior" achievement. The following video by YouTuber "Kreeper V" helps with this and gives very helpful tips along the way.
Volume 2 starts at "22:29" and ends around "37:42."