The Outer Worlds

I found a very good place to get this and a lot of the other achievements which require you to grind kills.

When you get to Fallbrook on the planet Monarch, you can find someone called Catherine Malin who will give you the quest ‘Slaughterhouse Clive’.

When you get to the front gates, save before entering.
(For this achievement, you can make another save just before the pig room if you want to speed things up. However, if you are planning to grind other kills, then make a save outside the front gates.)

1. Clear out the few enemies at the front and get the key off the leader.

2. Enter the compound and defeat the enemies in this area or run straight through and into the main building.

3. After a couple of rooms you will be in a large room downstairs where they keep all the live cysty pigs.

4. Go into crouch and simply hit them all one by one with a melee weapon. These should all count as stealth kills.

5. Reload your save. Rinse and repeat.

- To hit someone with a "sneak attack" you must crouch and melee an enemy without getting "noticed"
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- There's character stats you can upgrade to make your MELEE attacks stronger  such as strength and Melee Skills which would help to "Kill" an enemy with the sneak attack obviously
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- Basically there's lots of grind spots for this where you can use the Save Trick before killing groups of enemies to help with this cheev, I did it in the C&P Boarst Factory Grind Spot

- I advise you make an effort to kill the weak enemies with sneak attacks regularly throughout your game play to avoid having to grind out these kills later :)
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- Remember the SAVE trick to help you grind this out faster
One trick that helps with all of the "do this X amount of times" cheevs...use the SAVE feature to RELOAD SAVES helping you grind those out easier. *However people have said that it can cause the tracker to stop going up...so if this happens, try saving after you do one run, SAVE on a new file, then RELOAD the old one. Rinse & Repeat.

All of my HD Achievement Guides for The Outer Worlds can be found here! :) (Mobile Friendly)
https://www.bradleafsfan9.com/the-outer-worlds

In this video guide I will show you how kill 50 enemies with sneak attacks. Now first things first. If you started your character right off the bat with increasing the strength and dexterity attributes. The damage will for melee weapons will be greater. Also making this achievement easier. Another way to make this easier would be to put points into the melee category under skills. Also your companions have some perks to help. Nyoka and Parvati both have the perk called: Heavy Handed for increased melee damage.

Now in order for this achievement to actually count, they will need to be one shot killed. The higher the damage the better the chance. Don't forget you can tinker with melee weapons to make them stronger. A good spot to get kills for this would be on Monarch. Look to the South by the water. There will be a factory called: C&P Boarst Factory. Head there and once you get there make a manual save. Now go ahead and kill everything in the factory. Including all the people, pigs, robots, and don't forget the worms on the floor count as well. Once you are done reload the manual save and keep going until the progress stops.

Now this is very important. You won't get progress for the same exact enemy. So when you get a sneak attack kill, it won't count again. Just keep going after the factory if you need more kills. Once you get the final sneak attack kill the achievement will pop.

The achievement unlocks when you kill your 50th enemy with a sneak attack. To perform a sneak attack, you must have 20 points invested in sneak under the stealth skill tree and kill an enemy while crouched without alerting it. Sneak attacks can be performed with either ranged or melee weapons.

In order for the kill to count towards the achievement, the enemy must be unalerted. Thus, the goal is to one-shot kill the target or use a silenced weapon where the first shot does not alert the enemy. Weak enemies, like sprats, are ideal. More robust enemies are more easily killed on the first hit if you have unlocked TTD location hit effect for the weapon you are using. TTD location hit effect unlocks at level 20 for ranged weapons and level 40 for melee weapons.

Critical attacks to the head in TTD mode with location hit effect are most likely to result in one shot kills. Note that if you have TTD location effect unlocked for melee weapons, you will also be able to deliver power attacks while crouched that unlocks at level 20 for melee weapons. Power attacks are more likely to one-shot kill the target although weak enemies like sprats (or worms and pigs found in the C&P Boarst Factory on Monarch) can be killed with a regular attack.

The achievement will almost certainly unlock during normal game play. Sneak attacks are very advantageous and the player will, most likely, rely on them frequently regardless of the selected difficulty mode including supernova. In fact, sneak attack kills are of particular value to supernova players because of the necessity to avoid exposure.

For those that want to grind early in the game (This approach also works for any difficulty and any character build provided that sneak is at level 20 or better):
--For convenience, turn on the achievement tracker. Designate this achievement as a favorite so you can track its progress.
Note 1: If you are grinding, you might want to combine it with one or both of the following achievements. Use a tossball stick or blocker as your weapon if going for:

Use a plasma weapon if going for:

If you want to grind for one or both of the above achievements, designate them as favorites as well so you can track them.
--Proceed through the game until you reach the town of Edgewater. Avoid killing sprats.
--Return to your ship and sleep till night-time. Make a manual save on the ship. Make note of it and don't over-write it until after you get the achievement.
--Return to Edgewater. Enter the main entrance and immediately exit again. This banks an auto-save. If you are playing on other than supernova difficulty, you can make a manual save just outside the main entrance instead of relying on the autosave. If making a manual save, do not overwrite the save you made on the ship.
--Select an appropriate weapon especially if you are going for tossball or plasma weapon kills.
--Turn left as soon as you exit back out of town and circumvent the perimeter of the town counter-clockwise. Note a Spacer's Choice poster on the wall to your left that says, "Taste the Freedom" and turn the corner.
--Shortly after you turn the corner, you will come across a number of sprats. They will be asleep and are not easy to spot. The first is near the base of a big vertical pipe running down a structure to the right. The remaining four are on an approximate line between that sprite and the corner to your front left. Crouch and approach each one.
--Optionally, invoke tactical time dilation (TTD), , for extra damage and kill each sprat (). Note that for kills to count towards the achievement, you must be crouched and the enemy must be unalerted.
--After you have killed the 5 sprites, proceed around the perimeter to the far side of town wrt the main entrance just around the corner of what is depicted as the 'junkyard' on your map. There is no need to go into the junkyard.
--Kill another 6 sleeping sprats while crouching.
--After killing as many of the 11 sprats as is convenient, reload the auto-save you banked when you entered town.
--Repeat the process killing another 11 sprats or so and reload the banked auto-save.
--Continue killing sprats around town's perimeter & reloading the banked auto-save when you run out of targets.
--Some sprats are well hidden and hard to find If you have trouble spotting them, ignore them and reload the banked auto-save before you reach the 11 count. Similarly, if a sprat is alerted, ignore it unless you want tossball or plasma weapon kills.
--Keep an eye on the tracker. When you have killed 50 sprats, the tracker will get to 100% and the achievement will pop.

Note 2: If you, accidentally or intentionally, lose the banked auto-save (or manual save made outside the Edgewater entrance), reload the manual save you made on the ship. You will retain all progress towards the achievement. Return to town, make another banked auto-save at the entrance by entering & immediately exiting. Resume progress towards the achievement by sneak killing sprats around the perimeter.

Note 3: The sprats can also be killed during the day but they will be active. They are very quick so killing them is more of a challenge. They alert more easily so it is harder to get sneak kills.

This can simply be done by shooting explosive barrels/crates or mines in sneak mode. I did it in the first area on HRS-1084, before you turn the power back on there are 12 barrels/crates/mines the you can blow up so if you save as you enter the station you can destroy all 12 and reload as necessary until you hit 50