Last month I ran two games, both Powered by the Apocalypse, in the first, a game of Viking World, I feel like the game ran aground a bit on some player assumptions so for the second, a game of Adventures on Dungeon Planet, I was upfront about the assumptions of the game and as a consequence it went much more smoothly. But the whole thing has had me thinking more about the assumptions that players and game masters bring to games.
