Black Ops III - Zombie Chronicles - Acted Alone - Attempt 01

Acted Alone
In Verrückt, headshot 20 zombies in the courtyard from the second floor of the Asylum.
This trophy is easier said than done. The courtyard is the middle area that contains the fountain. Zombies will spawn from the ground around it and they will travel to the closest window or staircase.
Any zombie found entering the Asylum or that are walking up the staircase are invalid.
Try and reach the 2nd floor as soon as possible and equip a gun that can easily headshot zombies. The earlier the round, the fewer amount of health the zombies have for really simple headshots. Since there is no PAP, you really need a decent weapon, like the Shieva (very early rounds), an AR or an LMG.
A perk that is highly recommended is Deadshot Daiquiri, which auto-locks to the head of any zombies. You can get it from the Wunderfizz machine next to the Mystery Box.
You must patrol above the courtyard, spotting any zombie coming from the ground. You'll figure out the spots they come out from and take them out easily. You have to be aware of the other zombies that are actually in the Asylum to not die. You must do this for several rounds and hope that most of the zombies actually spawn in the courtyard. This is more difficult solo due to the job of constantly looking over your own back.