Heart is a roleplaying game of weird dungeondelving about doomed people getting exactly what they desire, no matter how badly it turns out for them. It is published by Rowan, Rook and Decard and is set in the same world as (and directly beneath) another of their games, Spire.

Everything in the book drips with flavor, and, often, blood. The Heart is a tear in reality deep under the city of Spire. Above ground, dark elves struggle to free themselves from the colonialist oppression of aelfir, gnolls fight for their independence, and humans are just doing their own archeotech thing. None of this matters below, in the City Beneath.

Near the surface, it’s still somewhat sensible, caverns and tunnels and cursed train networks. Things get increasingly surreal as you delve deeper, closer to the irreality of the Heart itself. Absolutely anything can be found here: predatory libraries, assorted heavens and hells, mythic beasts, wild forests, the True Moon. It used to be a slightly more sensible place, before an overambitious engineering project of the aelfir ruptured the Heart 150 years ago, causing it to spew its weirdness far and wide. Now, populated havens and landmarks are scattered throughout the underworld, each place living by its own logic.

No one knows what the Heart actually is. Many people think they do. The very nature of the Heart means any of them could be correct at any given time, no matter how contradictory their theories. Alien terraforming mechanism, a nascent god, a benevolent slow-rolling apocalypse. The only things most agree on: it changes reality, it doesn’t understand us, it will give you what you want.

The player characters are the ones desperate, driven, or deranged enough to take the Heart up on this promise. They want the impossible, and they will go through the phantasmagoric hell to get it. The character classes can be thought of as D&D analogues thoroughly infected by the Heart. Instead of a ranger you get Cleaver, a possibly cannibalistic hunter that derives memoreis from the things they eat and becomes a progressively more fucked up were-beast. Instead of a rogue you get Deadwalker, stalked by their own death, and Incarnadine, a priest of the god of debt. Deep Apiarist, Heart’s druid, has a beehive in their ribcage and strives to maintain order in the ever-changing chaos. Junk Mage is a fairly straightforward warlock, if you discount the “junkie” part of it, borrowing power from a patron or three. Hound is a fighter that’s joined a loosely associated citizen militia of the Heart, while Vermissian Knight is a fighter that likes trains so much they wear one. Finally, Heretic is, unsurprisingly, a cleric that worships an underground, “true” moon; and Witch is a spellcaster infected by heartsblood itself, with barely any side effects at all, so long as they don’t ever experience any kind of strain.

Aside from classes, characters get an ancestry and a calling. Ancestry has no mechanical bearing, but offers characterisation ideas and asks how you got into the Heart. Calling is the reason you’re there, and is the basis of character advancement. To me, it is the standout feature of the system. Each calling comes with an ability and a big list of minor, major, and zenith story beats. The beats are various accomplishments, and range from “charm someone with tales of your exploits” to “find the final secret you have so desperately sought and use it to solve your impossible task”. Players pick two of these beats, typically at the end of a session, and inform the GM of their choice. Should they accomplish a beat during the next session, they gain an ability of corresponding power.

A genius bit happens here, a ludonarrative assonance: players tell the GM what they want their characters to experience, the GM, as the Heart, does their best to match these desires, warping the reality of the game in the process. Do you want to kick someone off a high place? There will be a high place where you’re going. That’s why Heart doesn’t have a stable map, only a list of landmarks.

Zenith beats, like the final secret one I mentioned, are very hard to achieve, and not everyone will manage to do so before their untimely but likely deserved death. The reward for doing so, a zenith ability, is incredibly powerful but typically lethal as well, or at least transformative enough to remove the character from play. It gives you a chance to completely steal the scene, overcome impossible odds, and end your character’s (adventuring) life on your terms.

Zenith abilities are cool and flavourful (though a few too many of them are essentially “you utterly destroy a place and yourself in the process”), but come a scene too late. You get them as a reward for accomplishing your utlimate task, but they would have been so much more useful while you were trying to accomplish your ultimate task. Even if the character still wants something after their main goal is met, do they want it enough to destroy themselves to get it?

It’s obviously possible for the GM/Heart to pull out some greater calamity to threaten their success or someone they came to care about, but to do so without it feeling cheap takes more skill than I had mustered for our campaign. It took quite a bit of effort to bring even two of the PCs’ stories to culmination simultaneously. The one that “ascended” first did use their zenith ability to help out the other, but it was mostly to show off. This meant the game had run its course, even though the third character still had goals to attain: with 2 of 3 characters retiring, we saw no reason to continue for another session or three with substitutes.

The core mechanics of Heart are very similar to Spire. You still assemble a die pool of d10s, one for free, one more if you have an appropriate skill (what you do), one more if you have an appropriate domain (where/to whom you do it), and another one for mastery (circumstance or abilities). Highest die determines whether the action ends in success, success at a cost, or failure. Difficulty works slightly differently: instead of reducing the die pool by one or two dice in Risky or Dangerous situations, Heart takes away one or two of the best dice after the roll. It is, as you can imagine, quite punishing, but countered by having high-quality equipment.

Much like in Spire, failure and success at a cost give the character stress in one of five tracks: Blood, Echo, Mind, Fortune, and Supplies. After a character gains stress, the GM rolls a d12. If the roll is less or equal to the total stress the character has, they suffer a Fallout, minor on a roll of 6 or less, major otherwise. This means even a character overflowing with stress has even odds of only suffering a minor fallout, making Heart characters quite resilient. Furthermore, the only way to suffer a severe fallout that likely ends the character is for a player to choose to upgrade a major fallout after suffering another major fallout. In Spire, the fallout die is d10, and the severity of the fallout depends on total stress at the time, not the roll, with 9+ stress guaranteeing a severe, character-ending fallout.

There’s a list of fallouts for each category, some are immediate and others last until dealt with, likely at a haven, in exchange for resources – useful stuff you scavenge, loot, or butcher along the way. Each resource has a die rating measuring its potency, from d4 to d12, a domain it belongs to, and sometimes a tag. For instance, you might have a Harpy’s Heart (d6, Wild, Deteriorating). A lot of character abilities interact with resources in some manner, e.g. a Cleaver can eat any resource to gain corresponding domain for a scene.

Finally, stress recovers differently. In Spire, you cleared an amount of stress depending on the severity of fallout you suffered, and could engage in character-specific activities to relieve stress or even hide away and let time pass, clearing it all. In Heart, you clear all stress from the track you just took a hit to on a minor fallout, and all stress from all tracks on a major fallout. You can also use equipment and abilities to clear stress, but that usually involves a check, which means the risk of further stress.

The main reason for all the changes is the larger amount of checks players are likely to make in Heart. Spire is typically a game of intrigue and investigation. Any misstep could spell your doom, so you tread carefully. Characters slowly accumulate stress until everything goes wrong for them at once.

In contrast, Heart is often a game of reckless violence. You’re already doomed, you’re already in Hell looking for your own personal Heaven, what’s one more gunshot wound. Stress comes and goes frequently, it’s the fallouts that stick around, and you have to make it to the next haven to fix them.

Combat is frequent, and it is quite swingy. You can overcome even a dangerous foe with only a couple of good rolls, or you might flail at them ineffectually for a while, suffering multiple fallouts. It’s a bit of an issue, as every fallout suffered pauses the game as the GM flips through the book looking for one that fits the situation. This didn’t feel quite so disruptive in Spire, because there weren’t as many rolls.

Combat is also, unfortunately, not quite deep enough. No matter what cool abilities you might have, how imaginative the monsters are, or how impactful the fallouts, at the end of the day you’ll be rolling Kill checks until the enemy is dispatched – and, again, the combat is quite swingy, so sometimes it takes a while. In addition, not all classes have good access to the skill. Usually, advances that grant you a skill come loaded with some kind of flavourful side benefit, like the ability to see in the dark or harmlessly fall from significant heights. Then they have a more generic advance that simply grants one of a few skills or domains that are not as fitting for your class – and for some classes that includes Kill. Spending an advance on it just doesn’t feel as satisfying. You can get away with playing the supporting role in a fight occasionally, or have an objective other than killing whatever’s trying to kill you, but most of the time it’s Kill or be Killed, and characters that are bad at it feel like they’re not pulling their weight.

While other fallout categories are fairly straightforward – your Blood is spilled, Supplies run low, etc., Fortune is the odd one out. It mostly deals with the consequences of poor decisions made (or just plain bad luck). You might take the wrong turn and extend your journey, piss off the locals, or become their unwilling messiah. In addition, some places and creatures have their own custom fallouts associated with them, like a mind-controlling location seeping deeper into your brain, or a ghost possessing your body. These don’t always work seamlessly, and sometimes mean the signature threat of a scene is never realized simply because the dice didn’t cooperate, but it’s a very interesting idea nonetheless, and something I’d like to see more of in future supplements, should they happen.

Fallouts are tricky in general. There’s an art to picking them so as not to overwhelm the characters. At one point, the entire party in our game was suffering so much it became comical, with multiple broken limbs, ragged nerves, blinded eyes, weird growths, etc.. This isn’t an issue with the rules, there are many once-and-done fallouts I could have given them instead, just something to keep in mind. The maleable nature of the Heart offers a fix for this as well, you just have to be flexible enough to take it. Does the party desperately need a break? The Heart can provide a haven that wasn’t there a moment ago, perhaps an all-too-convenient pub with absolutley no dark secrets hidden in its cellar.

In a certain way, Heart is the polar opposite of OSR in this regard. OSR, generally speaking, wants to establish the dungeon, draw the map, provide random encounter tables, then watch the characters deal with the problems as they come, in a “fair” fashion. Heart makes everything up as it goes. Do you need healing? Here’s a haven. You picked a beat to punish someone? Meet an absolute bastard of a person. Low on resources? Well go get them, that cursed plesudodeer isn’t using its bones for anything significant.

Broadly speaking, there are two kinds of campaigns you can run in Heart, both centered around travel. The first, and the kind we played, is a one-way descent. Somewhere deep within, the characters will find what they’re looking for, even if they don’t know what it is yet. The other focuses on a hub, probably a haven, that you try to protect by venturing back and forth. Should you be interested in it, you’ll probably want to pick up Sanctum, a small supplement written just for this. Either way, journeys play a significant role. The book is filled with unique locations and it is a delight to explore them. In fact, our campaign went for longer than it probably should have simply because I wanted to fit more landmarks into it. Even then, we haven’t even seen a third it.

It’s a shame, then, that my biggest issue with the game is the way it handles the actual journeys between the landmarks, the delves. When the GM prepares a delve, they determine the length of its resistance track, which functions much like a health pool, tracking the overall progress of the trip. As the party overcomes challenges on the way, they inflict stress on the delve, filling the track. Once the track is filled, the delve is over. Just like combat, this is very swingy: normally you inflict 1d4 stress, with a typical delve having 8-12 resistance. But while a combat taking an extra roll or three to finish is not a big deal, a delve requiring more obstacles than you have prepared means you need to rapidly improvise. And there’s no random encounter tables or even a roll to suggest the nature of the next obstacle – which is fine so long as the GM/Heart knows what should happen next, but leaves them floundering otherwise.

One of the reasons for this rule was giving meaning to delve items: grappling hooks, compasses, air-tanks, etc.. When you use a Delve item in overcoming an obstacle, you use this item’s die rating instead of the default d4 – they’re a direct analogue of Kill items i.e. weapons. Except thematically this doesn’t actually work. Having a grappling hook doesn’t make the check for climbing up a wall any easier. Instead, it means you’re likely to face fewer obstacles after you’ve climbed the wall.

Every time our party overcame an obstacle, inflicting stress on the delve was an afterthought, the least interesting part of the situation that was also the most mechanically significant one. By the second half of the campaign I had given up on tracking delve resistance, instead simply declaring the party had arrived at their destination as soon as I had used up the ideas I had for travel encounters. Thankfully, none of the characters had taken any abilities interacting with this part of the rules, so this wasn’t a problem. Still, completely cutting out the mechanic for the main activity of the game is not great.

Despite the game’s flaws – and to be clear, most of them are quite minor – I loved my time running it. In a hobby drowning in dungeoncrawling games, in grimdark and despair and lovecraftian horror, Heart offers a unique experience. Wonder and horror, grime and grandeur, hope and tragedy, alien and personal. Every monster is utterly sad, but it will still try to eat your face. Everything has gone wrong, yet people still live there. Not just live, they make art, they aspire. The characters are doomed, but they’re powerful. It’s their humanity that drives them towards becoming inhuman. Drives them deeper into the Heart.

Perhaps you’ll find what you’re looking for in Heart, too.