So I was building the first true dungeon for my weekly Labyrinth Lord game. Some of the players have never played old school before and all the PCs are first level. I carefully crafted the setting based on giving the players meaningful choices, encouraging exploration of not just the physical space but also the history of the structure, and areas with unusual features they can play with.
And then, at a critical choke-point, I dropped in a critter with 7 hit dice who can only be harmed by magical weapons. Just what the heck is Trollsmyth smoking?!?
What I'm smoking is pure, unadulterated Moldvay/Cook D&D. The Moldvay Basic book covers only levels 1 through 3. And in the monster section you can find the 5 hit-die ochre jelly (can only be harmed by fire or cold), the 4 hit-die giant rattler (with save-or-die poison), the 6 hit-die minotaur, the 4 hit-die medusa (with her save-or-be-turned-to-stone gaze and save-or-die-from-poison “hair”), and the full range of classic chromatic dragons. And while the wandering monster tables embrace the notion that deeper levels means tougher monsters with richer treasures, the outdoor encounter tables in Cook's Expert book toss even that fig leaf aside. One in eight random wilderness encounters results in a roll on the dragon subtable, and the weakest critter there is probably the 5 hit-die hydra. Oh, and since these critters aren't in their lairs they're not likely to be carrying much in the way of treasure. Just about all you'll win from killing them is your life, plus a paltry handful-hundred experience points.
Which was just fine for us way back when. Our models were “Choose Your Own Adventure” books where you had to outwit your foes because fighting just wasn't an option in most of them. We also looked to the stories of Sinbad and Odysseus, who didn't slay the roc and cyclops, but outwitted them. And of course there were the Saturday afternoon Harryhausen flicks, where, again, the monsters were not usually defeated by mere swordplay, but by being shoved off ledges, tricked into tar pits, fought with other monsters, or just plain running away.
It's not for everyone, and if you're not used to it, it can seem a bit odd at first. I think it best catches the real thrill of exploring a wild place, where not everything is safe and nothing is predictable. It does require strict adherence on everyone's part to noism's ur-rule of good play. A DM who is too quick to say "no" or is out to get the players can really sour things fast. So can players who are unimaginative or too timid. And it'll really crash if everyone isn't on the same page. I'm not a huge fan of the "social contract" thing, but if someone wants this sort of play and the rest of the group isn't on board, gears will grind and the game is likely to lurch a bit.
But when it's working, the game just sings. The players are having fun because they have no idea what will be behind the next door, and they know they can really get their hands dirty mucking about with the setting. The DM is having fun because there's no telling what the players might try next. I love this kind of gaming, and I feel very, very lucky that I've consistently been able to find the sorts of players who enjoy it too.
UDATE: Mr. McKinney touches on a similar topic.