People Playground

At the time of writing, the currently displayed description is wrong. The achievement now requires you to play for an hour in one session without killing anybody. This means "active" play meaning you can't just leave the game open in the background or go AFK. I created a simple AHK script that will spawn a chosen item and then delete it (and also press the arrow keys and click for good measure) which will repeat infinitely until the script is stopped.

Download here
or copy+paste the below code

#MaxThreadsPerHotkey 3
s::
#MaxThreadsPerHotkey 1
if KeepRunning {
	KeepRunning := false
	return
}
KeepRunning := true
Loop {
	Send {q}
	Sleep 500
	Send {Up}
	Sleep 500
	Send {e}
	Sleep 500
	Send {z}
	Send {z}
	Send {z}
	Send {Down}
	Sleep 500
	Click
	if not KeepRunning
		break
}
KeepRunning := false
return

TL;DR

• Download and start script
• Open People Playground
• Enter a room (I recommend Default)
• Pick any item except for a person (a person being spawned in is not required for achievement)
• Press 's' to activate and deactivate script
• Let it run for an hour

They've changed the criteria for this so please edit on the page

The criteria is - Don't kill any ragdolls for 1 hour.