Overall, this achievement is not hard, but it is possible to make a mistake, therefore I would like to re-emphasise point 1, DO NOT even equip other weapons, put all unrelated items into the store and sell unwanted items to reduce the risk of a mistake. These enemies are a drain on your ammo with the Plasma Cutter, and 80% or more of the time, there will be an explosive red canister or generator in the immediate vicinity that can dispatch them in one (not the Pregnants or Dividers when whole, only when they are broken into smaller enemies, using a canister on these whole only opens them up).

The Plasma Cutter can deal with almost anything but Swarms (the creeps that jump your back), Pregnants (the ones that drop Swarms if you shoot them in the Torso), Dividers (the ones that break down into heads or other individual body parts) and Guardians that are stuck on the walls and spit out single, immobile lurkers. Upgrade it accordingly so that you can continue with its HP upgrades, but air and other parts are not essential. A maxed out Plasma Cutter will make the final levels easier. Be sure to find the 3 Plasma Cutter upgrades in Chapter 2: Intensive Care - Heat Pack (after destroying the barricade, it is in the Clinic), Chapter 3: Collision Course - Ammo Capacity (it’s available in the store for 11K credits from this point on) and Chapter 8: Search and Rescue - Weighted Blades (in the maintenance room just before you take on the Leviathan Remnant). The Suit is not really necessary earlier than this. During the start of the game, just go for the Plasma Cutter upgrades and then start making inroads on the suit at around Chapter 3. There is enough Power Nodes in the game to max out the Plasma Cutter and almost your Suit if you take the time to collect them. Use your power nodes solely for Suit and Plasma Cutter upgrades only, they’re no good on other weapons that you can’t use. Sell the rest back to the store for credits. Only stock Medkits, Plasma ammo and a Stasis pack or two. Use of Stasis, Kinesis and Melee does not affect your playthrough. To be safe, don’t even equip them, return any other weapons and upgrades to the safe to avoid any mistakes and free up space. There are however a few tips to consider: - You can pick up other guns throughout your playthough, just be sure NOT to fire them.

It is easily doable on medium difficulty and those who are familiar with Dead Space could do it on Impossible difficulty without any real issues. This achievement is for completing the entire campaign only using the Plasma Cutter.

Plasma cutter only dead space