DOOM 3: BFG Edition
59 Achievements
50-60h
Too Slow, Fool!
Kill 5 enemies at once while in Hell Time in RoE
1.2%
How to unlock the Too Slow, Fool! achievement in DOOM 3: BFG Edition - Definitive Guide
Right after getting the keycard from Sarges storage cabinet that also has the double barrell shotgun. This room also has the super turkey puncher game. Once you start backtracking the screen will turn red and 8-9 zombies come out of hiding. Just slow time and get out your shotgun.
Now just go through game and when you find a group of 5 or more enemies (most likely a group of zombies) just use it and shoot them all and you should get your achievement.
This is easily obtainable in Erebus Level 3. When you get the Super shotgun, the card, then remove power cell and leave the room, 5 zombies will appear (you can kill these to get the trophy but it's easier in the next area). Your screen will turn red. Many zombies will be there (at least 15), activate Hell Time and kill 5 of them, throw grenades to make it faster.
You will first obtain Hell Time for the Artifact once you defeat the Helltime Hunter boss. Hell Time is this game’s version of slow motion. It is activated by using the Bloodstone (see “Evil Nightmare”). A good spot for this is in Erebus Labs Level 3, but can be done anywhere there are five enemies together really.