Glitch that works as of 17/08 - 2020You do not need 8 people for this. Personally I did it with 5, but it should be possible with 4.
I stumbled over this video on youtube and the glitch still works after the recent patch. This method also works for the 1300 kills. On a good run I got around 140 kills in a game.
How to get the achievement using this glitch:
- Counselor #1 and Jason follow what they do in the video. up until the 2-minute mark.
- The remaining counselors look for the radio antenna and call for Tommy.
- Jason needs to kill Counselor #2 and #3, One of them will respawn as Tommy.
- Jason kills Tommy, then the remaining counselors that is alive.
- Follow the steps after 2 minutes in the video, and keep killing counselor #1.