Dungeon World is a fantasy heartbreaker powered by the Apocalypse World rules. While it has a few clever ideas, its nowhere near as smart and dangerous as the earlier game, and as with most fantasy heartbreakers, the ultimate question is always "Why this as opposed to D&D?"

((Note: this is a reading review, not a playtest review)).

The basics of Dungeon World are about exactly what you'd expect. Classes, the standard six core stats, a list of moves like "Hack & Slash" and "Defy Danger" and a brutally simple system of roll 2d6+stat (between -3 and +3), over 10 is a success, 7-9 is success with complication, 6 is fail and mark XP.

The system has some truly elegant bits. The Spout Lore and Discern Realities moves are the best general Knowledge and Perception systems I've seen in any fantasy RPG, and worth stealing. Each character class has a list of Bonds-statements that tie one character to another (my favorite is the Wizard bond: "[x] is important to events to come. I have foreseen it!") The GMing advice, on playing to the fiction, mostly empty maps, and using Fronts and Portents to advance the plot and provide enemies, is all top notch and valuable to newbies and experts alike. And finally, I really like the general presentation, the artwork, and the quotes from fiction in the margins.

What I do not like is the system, which is very chancy and doesn't give a lot of room for modifiers-most characters will start with +2 in their best stat, so a +1 bonus is a 50% improvement in character power. The classes are oddly restrictive--no elven clerics, halflings are fighters or thieves, mostly to emulate Old School style, which is a weird choice for a game based off of the relentlessly modern Apocalypse World. Bonds are neat, but I worry that they might pull the group in contradictory directions, or be too densely webbed as written. The system for developing towns and villages is really strong, but misplaced in a game that's about adventure and danger.

Ease of GMing is a very important part of any fantasy game, and this is where Dungeon World and I part ways. D&D4e hits it almost directly square on the head-I can trust that most monsters will run properly out of the box. D&D3.x does it poorly, but at least provides some guidance in the form of Challenge Ratings. Dungeon World leaves it up to you, with an exhaustive bestiary, but no guidance on how tough monsters are. Sure the 20 hp d10 damage behemoth is more dangerous than a 6 hp d6 damage giant rat, but how much more dangerous? Encounter design is really really soft. The exploration rules are similarly abstract. Characters have encumbrance and limited rations which get used up in the delve, but there's nothing about starving to death in the dark, or even why you'd want money beyond a few hundred coin to upgrade your starting weapons. Characters get more options, but they don't get stronger or hit harder, so you can't rely on the loot-level treadmill to drive the action if the plot falters. The style of the game might be really good for one-shots, or death heavy old school dungeon crawls, but then the GMing advice should be aimed at "4 hours of subterranean terror" instead of longer campaigns.

As I said, there are bits and pieces that are really clever and that I can see using in any fRPG campaign going forward, but I just can't see myself running this game over D&D4e, 13th Age, or even D&D5e or 3.x. That's why these things are called fantasy heartbreakers; someone pours their life and soul into them, and then everybody just plays D&D again.