The Council
42 Achievements
4-5h
GOG
Quick
In the same game, choose 20 answers before the time is up
54.8%
How to unlock the Quick achievement in The Council - Definitive Guide
themindisacity
You'll get this without trying. About half of all dialogue choices are timed, indicated by a bar below the choices. Simply make a decision before the bar runs out. If you've succeeded in all timed dialogue instances, this will unlock somewhere in Episode 1, Quest 3.
Tassie, Tiger
Make a choice of answers before the timer runs out 20 times. You should get this in Episode 1. There are more than enough choices.