I can't tell you how relieved I am to see blood on my own sword. Kingdom Come: Deliverance is a historical first-person roleplaying game committed to an unusual degree of realism, from how (and how much) you fight to the world and the people who occupy it. You wander 15th century Bohemia as a minor player in a real historical crisis—the Papal Schism—but free to follow your own course. In this instance my course has taken me to a duel on a muddy forest pathway in the rain, a duel that I worry that I'm going to lose until I realise that the other guy is bleeding too.

When you fight somebody in Kingdom Come, your view locks on to your opponent and you circle one another with swords (and sometimes shields) drawn. You can rotate your angle of attack and defence around a dial, which dynamically alters your stance, and spring from that position into a slash, a thrust, or a block. These actions consume chunks of a regenerating stamina bar, which also doubles as a defensive buffer in front of your real (and very vulnerable) health. These are the building blocks of a combat system that is slow, heavy, and remarkably immersive.

Full disclosure: I'm a bit of a swordfighting nerd and I daydream about RPGs that take the concept beyond 'hit each other until somebody runs out of hitpoints'. Kingdom Come's developers clearly feel the same way and as such I was likely to enjoy this game from the outset. I want combat to feel weighty, stressful, confusing, even unfair sometimes, which Kingdom Come does. I understand that not everybody comes to an RPG for that experience. While there's a fair bit of The Elder Scrolls to Kingdom Come's open world, there's also a little ArmA, too—a willingness to plumb the uncomfortable consequences of realism.

So: I am circling this anonymous attacker by the side of the muddy path and my sword has blood on it. This is important because it means that I've hurt him. While Kingdom Come lets you see your own stamina bar, you aren't told how your opponent is doing. Instead, you need to rely on visual clues—blood is a pretty convincing one—as well as audio. Opponents are vocal and sound increasingly more tired and stressed as fights wear on.

I sweep my longsword up into my foe's flank and he barks 'fuck!' He's hurt and worn down, which is good to know because so am I. I press a bit harder, into a bind that I break by punching him, forcing him to block to one side so I can stab him in the other—I press right up to the point where I'm out of stamina but I'm convinced that he is too. I try to press my advantage, forcing another bind, but I lose this one. My view snaps back and spatters with blood, an unnerving first-person simulation of being punched in the face with a mail gauntlet. I don't block the next hit—I don't even see it—but then I die. Given that this early beta version of the game doesn't include saving, this is a terminal problem.

Even so, it's a genuine thrill. I gambled and lost. I love the drama that uncertainty about your opponent creates, and how much more convincing it makes the game. In real life, you can't truly tell how much energy somebody has left, how much they have in reserve—you can only test them and make a judgement, and there are consequences for getting that wrong. While there are certainly problems with Kingdom Come's combat at this early stage—occasional glitchy animations, controls that seem to lag from time to time—the system is enough to have me excited about the game on its own merit. I want to wander 15th century Bohemia, get into fights sometimes, and die alone in the woods sometimes. As you do.

That having been said, swordfights are relatively few and far between by the standards of a modern RPG. In peaceful moments Kingdom Come feels closer, surprisingly, to a detective game. The beta version has you tracking down somebody with crucial information about a recent bandit raid. He has vanished from his home village and you are given an open-ended remit to find him. This means talking to people and asking questions.

The version I played used placeholder dialogue and as such I can't really comment on the quality of the writing and acting (short version: it's obviously a placeholder). Instead, the system is what is interesting. The developers do not spawn NPCs in the world in response to player action—they are all there, from the start, doing their own thing. Demonstrating the game to me before I got my own time with it, technical designer Martin Ziegler called this "not cheating". That sensibility gives you an idea about what the game as a whole is trying to achieve.

If you know where your mark is you can run directly there (providing you can find it without map icons) and he'll be there and the quest will continue, no questions asked. Otherwise you need to talk together and piece together the information you need, and your success at doing so affects how straightforward your road to the target will be. At one point in the village inn Martin points at two men, armed, who happened to have just sat down and started drinking. They, apparently, are hunting for the same man as me—I just don't know it yet. Later, I'll fight them in the woods. They are here in the meantime because their AI has decided to go for a drink, but if I take too long with my investigation the story will play out differently: the guy will be dead when I get there, and I'll have to get the information from them instead.

This is an enormously ambitious way to structure a game and, honestly, it's not 100% there yet. As free as you are to do as you will in the world, vital information is often a persuasion skill-check away: improving your skill means nattering to people, which means having conversations that you don't really want to have so that you can return to a conversation that you've already had, repeat it, and do better this time. When the game acknowledges conversations you've already had and works around them, it functions well. When it starts to repeat itself, the skeleton of if/then statements underpinning the system is shown in an unflattering light.

This doesn't condemn the idea, but it does highlight the amount of fine-tuning it'll take to make it all work reliably for the majority of players. The notion that a branching story can play out fully dynamically in an AI-driven open world is something that other games have attempted, and it lives or dies on the extent to which its developers are able to anticipate and account for everything the player might try to do, every crucial NPC they might try to kill. Kingdom Come may well deliver on its promise, but historically I'd say that players tend to exceed whatever expectations developers place on them.

Even if Kingdom Come doesn't resolve these issues, it'll still have its combat system and world. The latter is beautiful in a starkly naturalistic sense. It's nice to wander villages and fields that feel like real villages and not game hubs, and to see a castle closely modelled after real history. The weather system is atmospheric and it's suitably easy to get completely lost in its forests, which is after all what forests in games are for. If I have a complaint its that village interiors feel a little static and samey, but then again I can't imagine that your average peasant in 1403 paid much attention to decor.

Kingdom Come feels like it's heading for cult classic status—it has the ambition, the idiosyncratic commitment to realism, and the Kickstarter backers for that. If it gets the time it needs to deliver on all of its ideas, iron out the bugs and flesh out the world with non-placeholder acting then it has a chance at removing 'cult' from that equation. If nothing else, though, I'm on board—there are few other games going set to let me lose longsword fights in the words on my own terms.