Call of Duty: Black Ops III

While this achievement can be annoying, it is made much simpler with the use of a few relatively common gobblegums. Whether you're playing alone or with friends, you should put them in your pack if you have them. If you have Perkaholic, Soda Fountain or On the House you can use those or a Wunderfizz machine to try to get the Deadshot Daquiri perk, which makes you auto-aim to the zombies head.

Fear In Headlights - Freezes zombies in place when you look at them. Want to line up shots on multiple zombies in the courtyard simultaneously? This will help immensely. Just be sure to let them fully spawn in first, otherwise they won't appear.

Undead Man Walking - Slows all zombies to a shamble. In later rounds, runners can rip off boards and escape your sights quite quickly. This keeps zombies off your back for a while and makes the ones below easier targets. Also lasts for 4 minutes!

Head Drama - All bullets that hit zombie count as headshots, useful for obvious reasons.

Extra Credit - Spawns a few 1250 point power-ups, allows you to open doors and get to the 2nd floor quickly. Also can be used to reach the power room and buy perks.

Killing Time - Freezes all zombies for 20 seconds. Very helpful if there are zombies attacking from behind and zombies in the courtyard waiting to be decapitated.

Solo

If playing by yourself, keep restarting until you're in the room with Juggernog. Starting with Quick Revive leaves you with additional purchases to make before reaching the second floor. On round 1, shoot each zombie 5 times with your starting pistol before knifing them. Rebuild boards and try to accumulate enough points to buy the Shieva from the wall (500 points) and remove the couch barrier from the staircase (1000 points). At the top of the stairs you'll be on the 2nd floor, looking over the courtyard down below. Zombies will rise from the ground down there and your job is to headshot 20 of them from this 2nd floor landing before they get inside the asylum or reach the stairs. Once they do, they're no longer considered being in the courtyard and headshots on them will not count. In the early rounds, use your Shieva to pick them off from the floor above as you occasionally glance back to check for zombies. This strategy is safe for around 4 or 5 rounds, in which time you can open the door behind the staircase barrier (750 points) and the door to the power room at the end of the hall (1000 points). Juggernog (2500 points) and Double Tap (2000 points) also wouldn't hurt. Once round 5 or so hits, things get hectic. Start using your gums to slow or stop zombies if you have them, but if you don't you should try to get 2-3 headshots in before moving away from the balcony, clearing out the zombies behind you. Once you get some space, check the courtyard again. If you want to open up the rest of the map and run circles to feel safer, go for it. Hopefully you won't need to go past round 7 to get this done.

Co-Op

A bit easier, as more zombies spawn and you have someone to watch your back. Have your partner either stand upstairs with you and watch for zombies coming from the stairs and doorway, or have them down on the first floor calling out courtyard spawns and drawing zombies to the spawn room window to be picked off by you from above. Gobblegums and perks are still effective here, so use them when the opportunity arises.

Call of Duty: Black Ops III Acted Alone Achievement Guide

Best way I found was to do this in CO-OP with some friends. You'll want to turn the Power on from the Jugger-Nog side of the map (left side of spawn) I would also recommend buying Jugger-Nog (2500 points).

A useful GobbleGum I would recommend using is Immolation Liquidation (Fire Sale) to get a good weapon from the box.

When you have Jugger-Nog and a good weapon, go to where the KRM-262 is located (Double-Barreled Shotgun in WaW) (up the stairs from the left spawn) and overlook the courtyard. A headshot give you 100 points (200 if double points is active).

Your friends will then want to cover the stairs and the wall directly behind you, whilst you shoot the zombies in the courtyard.

Hope this helped.

The way I got this achievement didn't really require any gobble gums but they would make great use Such as Shopping free or Wall Power

Make sure you spawn on the Jugg side (you will have to restart if you don't) then get enough points to open the Couch Staircase (750 Points) and for the Pharo (1,500 Points).

Once you have the Pharo, go to where you can see the courtyard and kill off the zombies until you have gotten your achievement

I did this solo and you have to watch your back as you are getting kills, a friend can be beneficial because they can cover you while you kill zombies that are in the courtyard.

If you ever run out of ammo just buy more Pharo ammo and if you have more than enough you should get either jugg or Double Tap.