
BTW, switch hunts are pretty much the same, and they're usually more annoying, since in keys' case, the colour bars will easily tell you which key you shall need, or even that wall piece is actually a door, for that matter. In a switch hunt, there is absolutely no indication, especially if the effect of said switch is far outside earshot. Yuck. Nasty.
I don't mind puzzles tho, as long as they're intuitive and reasonably hard. I never had much problem with Duke Nukem 3D combination locks, or solving Resident Evil 3 item puzzles, as you'll get enough explaination to think up the possible solution.
Usually, illogical and unintuitive puzzles are mostly found in RPG-styled games, as I told wildweasel about this earlier. He also shared his experience about he literally needed to look-get-touch-smell-taste-lick-insert into orifices every single object he came across just to make the game advance, or offer a new selection which'd progress the story further. I hate this. I really do.
Thankfully, Doom is totally devoid of this.