My experience with this game is somewhat limited relative to its sources: I played a convention one shot and a short game (4 sessions) with my local group with my wife as game master. But I think it is sufficient to give a fair review of the game in comparison to AW and D&D, games I've spent years playing.
I should however admit that D&D as a game and genre has lost much of its appeal to me (why is a topic for another day) so I plan to focus on well it replicates the feel of D&D and not my opinion on the genre.
Dungeon World Review
Same System, New Genre
So let's start with how it resembles the less familiar of its two ancestors, Apocalypse World.Like AW, it uses the dice mechanic of 2d6 + attribute where a 7+ succeeds. 7-9 means a partial success and 10+ being a full success. Failure serves to signal the game master to further complicate the situation.
Dice are used whenever a "move", or narratively important action, occurs. Attack a monster? Roll Hack and Slash. Climb down an abandoned well? Defy Danger if there's a threat (like crumbling bricks or hidden monsters), otherwise we skip to the bottom and what you find there.
The moves of Dungeon World tell us what is important about the game and how to handle it. Hack and Slash covers melee attacks and Volley does the same for range. Defy Danger is your catchall saving throw/skill check system. Spout Lore and Discern Realities tells your character something interesting about the situation from their education and perception respectively. Parley covers attempts to talk your way out of things.
There's a lot that harkens to the expedition model of dungeoneering. Encumbrance, while abstracted, is a move. Undertake A Perilous Journey exists for wilderness travel. Make Camp and Take Watch cover resting in dangerous environments. Supply covers the shopping trips and Recruit attempts to get meat shields hirelings.
Like AW, Dungeon World uses armor to absorb damage, though not very much relative to the damage thrown at characters.
Where it gets interesting is where it deviates from what one might expect from D&D. Last Breath gives one a chance to survive a brush with death (when your hit points drop to zero). Carouse lets you burn through your ill-gotten loot in true Conan style.
Magic items rarely grant a simple bonus. A sword might be flaming or sharp enough to cut through stone but that doesn't make the rolls easier. It might deal more damage or open up new moves instead. Mundane gear is simplified with less and there is much less shopping involved.
Adding to this is the fact that damage is based not on the weapon used but on character class. Fighters simply do more damage than Wizards even if they both wield daggers.
Experience comes from four main sources: failing rolls, following alignment, advancing your relations with other player characters, and fulfilling the main goals of the game: getting loot, exploring the world, and fighting monsters.
Finally the gameplay can be largely improvised. Like in many AW games by default the world is built up between the GM and the PCs thus creating a setting that both groups are familiar with. You could run the game in a "standard" D&D fashion with premade dungeon maps but there is nothing holding you to that.
Like (A)D&D
The world Dungeon World seeks to emulate is that of older versions of Dungeons & Dragons, like AD&D and Basic D&D, and not more recent systems like 3rd or 4th edition (Dungeon World was published in 2012 so comparisons to 5th edition don't come into it).Characters are defined by six attributes: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma which provide bonuses to rolls in a not quite linear fashion. Characters are also defined by a class and from that choice a race. A simplified alignment mechanic is also included (which unlike D&D's stick model, merely grants experience when you act according to your alignment).
Like D&D it includes hit points, based on Constitution and Class, and not AW's usual countdown clock. On the face of it makes the characters seem much tougher. However monsters in Dungeon World deal dice of damage, sometimes with bonuses, and characters soon appear quite fragile.
Characters advance in levels, which each new level bring more abilities and each level requiring more and more experience. Interestingly going up in level does necessarily add hit points or otherwise give bonuses (though characters do get to raise attributes which can have these effects). Characters thus grow more linearly than they would in D&D.
Spell casting sticks to the Vancian model of casting a limited number of prepared spells. Spells are not automatically lost when cast. That is fairly common option when using them however.
Unlike AW, combat tends to go back and forth for several "rounds". It's not quite like D&D but it certainly doesn't lend itself to the "one and done" behavior I enjoy in AW. Fights can get drawn out which means a lot more opportunities for failure and thus complications. Depending on how hard your game master is making his or her moves those misses can be worse than the initial fight itself.
Finally Dungeon World delivers the hordes of wacky monsters we've come to expect from D&D.
Conclusion
The result of merging D&D and AW is a game that seems a bit grimmer than most D&D games I've played. Characters are more fragile. Large monsters are scary, able to kill any character in just a couple lucky hits. Magical healing is limited and runs out quick. Monstrous hordes can easily wear adventurers down. This is not a game with the feel of a swashbuckling adventure.Dungeon World's strengths over D&D include an experience system that rewards playing towards the game's tropes. The alignment system provided also works well as a guide and incentive instead of the usual straitjacket. The somewhat more narrative style also works for me.
The game could use some more examples and detail in places. I was never quite sure what a shapeshifting druid could do, seeing as only a bare handful of animals are detailed in the book.
All in all however, I think it's an excellently designed game that delivers on what it sets out to do: create the desired feel of D&D using the Apocalypse World system.