You know how 5e has its skill checks handled mostly by asking around and the DM decides when a skill is appropriate? Dungeon World operates like that for every kind of interaction. You also don't have the uncertainty of having to pull a DC for the check out of thin air - it's always 2d6+relevant stat, where 6- is a failure, 7-9 is a partial success and 10+ is a full success. It's a bit open-ended what that means for many skill-like moves but others directly spell out the results.
Additionally, it's always the players who roll. Any attack or skill of the monster is defended against with an appropriate Defy Danger check. On that note, there's also no definite initiative system, but you should try and keep an even amount of chances to attack and pressure to defend (even in a system as simple as this, action economy is still very powerful).