As the achievement description says, you must fulfill these requirements throughout the whole DLC:
- Do not allocate any Praxis points, no matter how they were acquired: through level up or after collecting a Praxis kit.
- Do not fire any weapons. Takedowns (lethal and non-lethal) are not considered weapons and can be used freely.
- Do not throw grenades or place mines.
- Do not hit the "Fire Weapon" button even if your weapon is holstered.
- This counts as firing your weapon.
- Holstering and Unholstering a weapon with the "Holster Weapon" button is fine.
- On the PC the left mouse button is used during hacking and to fire your weapon. It is very easy to accidentally unholster your weapon after hacking and negate the achievement. One way of avoiding this problem is by going into the control settings and binding the "Fire Weapon" entry to a key you are unlikely to hit by accident. Note that you will then have to use that key to throw objects. Hacking still uses the left mouse button.
- Throw red explosive barrels and fire extinguishers.
- Pick up all items safely and sell them. However, it is not necessary to sell anything, because the starting credits (2500) are more than enough to buy all energy boosters and extra health items in the shop. Items that can be picked up include:
- Use healing and energy restoring items.
- Equip, aim, upgrade and reload weapons. NOTE: This seems to be incorrect, at least on PC version 126.96.36.199. To ensure you get the achievement, do not pick up any weapons at all, even your own. You will have to do the mission twice if you want the achievement and your gear.
- Equip explosives.
- Trigger and/or disarm explosive wall mines
- Trigger typhoon turrets (the rotating, beam-emitting turrets first seen on the third floor of the detention wing).
- Get compromised and set off alarms, although that would make your mission considerably harder. You should try your best to keep a low profile and stay undetected throughout.
It is possible to obtain this achievement by using explosive barrels to destroy the large crate blocking the necessary vent, and then using several of the small boxes laying around to access the raised area in the ducts (2 should be enough). These can be carried (in the proper orientation) though the ducts, and dropped carefully to turn them on end. A well-thrown fire extinguisher can destroy the gas mechanism, but may require several attempts.
- Factory Zero can be received simultaneously in one playthrough with all other achievements, aside from the That Old Adage (which requires upgrading Social Enhancer augmentation). You can, although, save just before talking with Quinn, talk to him and complete Factory Zero and then reload and upgrade the CASIE augmentation.
- All of the Above can be completed with some creativity (see discussion page). The more traditional way to complete it requires firing a weapon, Jump Enhancement, and Move/Throw Heavy Objects which would prevent completing Factory Zero. You could also create a save, spend Praxis points to complete All of the Above, reload the save, and continue on finishing Factory Zero.
- It is possible to do a "clean sweep" of enemies with melee take-downs and receive Ghost and Smooth Operator bonuses at the same time in every area. Ghost cannot be obtained after the constant alarm state is triggered after leaving Kavanagh's lab.
- The easiest way to complete this objective is to simply not pick up anything that is not used for boosting your energy (bars, boxes, and jars) or opening paths (pocket secretaries).
The achievement may not be unlocked, even if all criteria are met.
- One of the possible triggers for the bug is replaying the game with the "New game+" option. This issue also appears to extend to the pacifist and foxiest of the hounds achievements. It is recommended, if starting a new game, to not select this option.
- Another possible trigger that may cause the bug is picking up, reloading, and/or modifying weapons. If attempting this achievement, it is highly recommended not to be equipped with any weapons but only consumables.