The Quarry: How to be Bad and Kill Everyone for the Worst Ending
There are plenty of ways to kill everyone in The Quarry. Not including the Hacketts and other things lurking in the woods, environmental hazards and character choices can also lead to many a gruesome death. Making sure no one makes it through the night gets you the worst ending and the Hackett's Quarry Massacre trophy/achievement if you care about that sort of thing.
This guide won't tell you every way to kill each counselor (the only ones needed for this ending), but it will tell you the first time you can send them to the grave -- or in some cases, the first time you should. Some counselors should stay alive longer than others. To be clear, it doesn't matter if you kill the Hacketts or don't kill the Hacketts.
If you're trying to collect all the clues, evidence, and tarot cards or attempting to infect everyone, you won't be able to do either on this run. As expected, when someone dies, any of their subsequent scenes and sequences are simply skipped over. Try those when you save everyone or on subsequent attempts.
Note: Some story spoilers follow, though we've tried to keep the details to a minimum to avoid spoiling the deaths themselves, though even that is troublesome given the nature of The Quarry.
You can kill Jacob as early as Chapter 3 if you remove the rotor arm from the van. There will be a scream after Jacob and Emma swim in the lake. Jacob can investigate the scream or dive in after the rotor arm. Choose to dive in after the rotor arm, then choose to pull (not detangle) when his arm gets tangled in the wire.
If you disconnect the gas line to the van in Chapter 2 instead of taking the rotor arm, you can kill Jacob at the beginning of Chapter 4. As Ryan, choose to shoot into the bushes both times.
The first time you can kill Emma is in Chapter 4. Choose to open the trap door in the treehouse instead of searching through the bags.
You can kill Abi during Chapter 6 in the pool house. Don't shoot when Abi raises the gun at Nick.
You can kill Nick during Chapter 8 in the cave. As Ryan, don't stop Laura when she raises the shotgun in the room with the red light.
You can kill Dylan in Chapter 9. To do so, you must have chosen to kick the door in while playing as Abi and Emma in Chapter 1 and used the chainsaw in Chapter 5. Don't interact with the QTEs when Dylan is in the crane and being attacked.
You can kill Ryan in Chapter 9. Keep him alive through most of the chapter (it doesn't matter if you choose to let Laura "heal" him or not). When all hell breaks loose near the end of the chapter, after finding someone in the attic and falling through the floor, kill that someone as Ryan so you can kill Max later (you can't save that certain someone and kill all of the counselors). Choose aggressive, then fail the following QTEs as Ryan to cause his death.
You can kill Laura in Chapter 9. You must set this up during Chapter 7. Don't worry about the syringe when searching the police station. There will be a few more scenes (one where you speak to the cop in the morning and at night -- don't take the gun at night -- and one with two characters arguing). After that, there will be a scene where Laura is "sick." Make sure to grab the cop's gun and shoot him. (You have two chances to get the gun).
When things go to hell near the end of Chapter 9, Laura will die automatically.
You can kill Max in Chapter 10. Go to the dock and have him swim across to the mainland from the island.
You can kill Kaitlyn in Chapter 10. Don't do anything when attacked at the lodge.
That's how to kill everyone in The Quarry. Now that you've seen the worst ending in the game and the cycle continues, you can save everyone by following the true ending route (linked near the top of this article), infect all of the counselors, or see one of the many other conclusions by choosing a smattering of good and bad paths.