Having played a session, one aspect of Dungeon World that I like but didn't fully appreciate from reading the rules is that GMs do very little dice rolling. The only time I rolled dice the entire session was to determine how much damage was done by an enemy attacker. Instead, player actions trigger GM "Moves," and the twists and turns of play emerge primarily from the decisions the GM makes in the course of playing those Moves. Which is interesting, but is going to take some practice to do well.