I meant the blue/red/green doors in Doom and the corresponding keys you had to find there :) When I was playing it, I sometimes was wandering off for like tens of minutes to find the damn thing after I was done with the monsters :D
AH! Never played it myself, did not know that there even were colored keys and door in it. But I like the thought, that the designer of doom 2 could not come up with good puzzles, so they gave you a gun and threw a bunch of demons at you, to distract you from this fact. :D
