Just a brief account of the first OD&D session I ever ran, happened a few months ago, using the alternative combat system:
There were three brave adventurers: a beast of a Fighting-Man, a cunning Magic-User, and a wise Cleric. They had been hired by the Mayor of Garberg to clear out some old ruins of a troublesome tribe of orcs.
They fought their way through a couple of rooms, found a bit of treasure, and went down a level (big mistake!) At the bottom of the stairs was a stone door, which they opened with the aid of a secret panel which had to be pressed to open it. On the other side: six orcs, drinking ale and enjoying stolen meat with blades at their side.
Turns out our brave adventurers were lacking in brains. They charged the orcs, despite being outnumbered 2:1. The orcs slayed the Fighting-Man in one fell swoop, the Magic-User fell before having a chance to shoot off a Sleep spell, and the Cleric fell with her. The Fighting-Man was dead, but the MU and Cleric awoke later that night to find the room empty. They staggered back into town and went back to being farmers, deciding that the adventurer's life was too dangerous.