Prey: Mooncrash is the proof that procedural immersive sims can work

10 min readOct 27, 2020

I love immersive sims and I love randomness and procedural elements in games — and I’ve always wondered why these two don’t usually get along too well. For quite some time I thought that the reason is that immersive sims are always a very hand-crafted experience, created with meticulous attention to the tiniest of details — while procedural games are in many ways opposite of that, a chaos created by a random number generator, not some kind of a world builder’s master plan. While both procedural elements and deep emergent gameplay systems achieve the same goals — replayability and uniqueness of every player’s experience, — I thought that the former can only exist when there is not enough of the latter.

Prey: Mooncrash is the proof that I was wrong. Mooncrash shows that it is possible to retain the hand-crafted feel of the world and depth of systems while adding randomness, and the results are magnificent.

Prey: Mooncrash welcomes you to the hand-crafted, and yet unpredictable world.

While it’s certainly fascinating to see that Mooncrash is built entirely on top of the procedural mechanics, it’s not a shock to those of us who have been following Arkane for a while. The studios have been playing with certain smaller, but profound random elements in their previous games, and you could see they have been increasingly entertained with the idea. In Dishonored, on top of the usual emergent mechanics employed by immersive sims (such as semi-random patrol routes for guards), there were key items or mission objectives that would change from one run to another. For example, the identity and appearance of Lady Boyle, who you have to track and get rid of, is different each time, so you need to investigate and search for clues every time you replay the mission. In the sequel, Duke Abele can be found in different areas of his estate. These are just two examples — there are more variables like this in both Dishonored games.

These things definitely shake things up a bit and make it more interesting to replay the game, but nevertheless, they are examples of local variables that do not profoundly change the course of the entire campaign. What does to an extent is the system of bonecharms — while the actual locations of each bonecharm in the games are fixed, their properties are randomized. This means that you might find — or not find — a specific bonecharm that suits a certain play style very early in the game, and this might dictate the way you would tackle certain challenges, making each campaign run at least somewhat different. Prey (the base game) uses similar systems as well.

Random Bonecharms in Dishonored can significnatly affect your abilities and options.

The reason I love these procedural elements in Dishonored and Prey is because in immersive sims, any object, any hazard, any item and any ability can dramatically change the course of the game. It’s great when a game gives you lots of tools and choices and allows you to play your way, like all immersive sims do — but it’s even better if a game sometimes takes away some of these tools from you, or gives you something you didn’t have before, or spices things up in another unpredictable way. I love replaying my favorite games, and I would replay Dishonored and Prey just because of the world building and mechanics, but if the game makes it different and challenging for me every subsequent run, it’s even better.

Mooncrash cranks it all up to eleven. Arkane toyed with the ideas of random environmental hazards and world states while creating the base Prey campaign, but for different reasons they decided to cut these from the game (oh boy, how I wish they didn’t!). They returned to all of these ideas, however, in Mooncrash — an expansion which is as far from the safe and traditional “a couple of more levels and enemies” DLC recipe as possible. While retaining all of the key Prey mechanics, Mooncrash is somehow a completely different game, entirely built on the concept of procedural world building.

In Mooncrash, you play as five different characters, all with dramatically different abilities, strengths and weaknesses, all trapped on Pytheas — a big research facility set on the Moon. Essentially, your goal is to escape alive — escape repeatedly, by playing different characters and finding more and more ways to leave the base, while completing side missions and uncovering the secrets of the place. It’s all a simulation, so you can switch between the characters almost on the fly and start all over, if something goes wrong. There is a time limit — each run is split into five different “Corruption” levels 10 to 15 minutes long, and if you are still alive by the time Level 5 concludes (unlikely), the simulation resets. Basically, it will take you many, many attempts to run through the same spaces again and agin if you want to complete Mooncrash. Sounds like a horrible idea for an immersive sim, doesn’t it?

It’s not, because every run is different. The world itself is mostly static, so it’s not Diablo, Spelunky or Minecraft — you have the same geometry and set of levels, so you can gradually learn and memorize your way around. What is different each time is what these levels contain. The set of enemies is completely different, and they also spawn procedurally as Corruption levels rise. One run, the starting Crater area might have a few Mimics hiding and waiting for you; another run, it could be a couple of Phantoms; another run, it could be some Tentacle Nests. What you find on dead bodies, in crates, on tables and on shelves across Pytheas is completely different and entirely unpredictable each time — the same box or locker might contain a somewhat useless piece of junk which you could only recycle, or valuable ammo, or a Medkit, or a set of three Neuromods, or — the best of them all — the Delay Loop.Time artifact that slows down Corruption.

It gets crazier as you progress through the game and unlock the later versions of the simulation. Certain areas of the base might be out of power, which means that they are not only dark and scary, but also grav shafts and the monorail system don’t work and doors won’t open. Some areas might have dangerous radiation levels, or be on fire, or flooded and electrified. Last time, a bridge that comfortably led you to a room with the object you needed, was perfectly fine — but this time, it can be destroyed, and you would need to find a way around, or risk crazy jumps across chasms. If you think you’re getting used to it, on your next run you might not have breathable air in a certain area and you would need to manage oxygen reserves, or a dust storm might severely limit your vision in the Crater! This game keeps throwing more and more challenges at you, thus counterbalancing you becoming more familiar with its systems and hazards. And unlike the base game, when you can always rely on save and load to try and test different things or get out of trouble, in Mooncrash, if your character dies, you either switch to another one, or reset the whole simulation.

You need to go upstairs? Try to douse the fire first.

What is amazing is how Prey, being an immersive sim with dozens of options, always allows you to find ways to mitigate these disasters and solve problems creatively, often just barely clinging to life in the process. If you aren’t sure you can survive the next fight ahead, you can sneak around or take another way, or even switch to another character that you think is better suited for the challenge. If you happen to find a shotgun with certain randomly generated properties, you can take on certain types of enemies vulnerable to these effects. There is a pile of debris that blocks your way through a hallway? If you play as Riley Yu, you can mimic a small item and squeeze through an opening. The area you need to go to is out of power? You can either play as a security officer Vijay Bhatia who, if upgraded enough, can force open locked doors, or power the area by visiting the control center in the middle of the base. Got a dangerous dose of radiation? You can search for an anti-rad pill, or even create one using a fabricator. Can’t get through a Typhon Gate that is closed because an enemy happened to spawn nearby? Throw an EMP grenade and force the Gate to open for a few seconds.

I can’t stress enough how different every single run is because of the myriad of possible combinations and circumstances this game generates. In many games that take place in randomly generated worlds, the environments around the player are different every time, but what the player does is often repetitive — and thus it becomes boring after a while as you master the systems. In Mooncrash, it’s the opposite — while the world is mostly static, every run throws new curved balls your way, forcing you to think creatively and utilize the depth of many systems available in the game. One run, I was doing fine until I got too close to a procedurally placed radiation emitting barrel and got sick — instead of going towards my objective, I had to deviate and search nearby offices and medical stations for an anti-rad pill, all while the clock was ticking and more and more deadlier enemies were spawning nearby. Another run, I miraculously managed to complete one story objective just in the nick of time because I found a control module on a random shelf, fixed the broken monorail, rushed to another area, found a Delay Loop.Time item and reached the room I needed to go to at the very last second. Another run, I managed to survive an encounter with a Phantom only because I found a GLOO charge grenade 15 minutes ago, threw it at the wall, reached a higher ground and hid in the ventilation shaft. I could go on and on — Prey: Mooncrash is a generator of endless horror and survival stories and situations, all of which are enabled by the interplay of dozens of immersive sim gameplay systems and procedural unpredictability.

Perhaps the by-product of this approach is that Mooncrash invites you — if not forces you — to experience all different kinds and styles of gameplay Prey supports, instead of relying on just the one you prefer. This is a controversial decision, I have to admit. For instance, I’m a stealth player, and whenever a game allows me to play slowly and quietly, I do so. While Prey is an assault-focused immersive sim, I managed to complete large chunks of it by avoiding enemies, or killing most of them with just a silenced pistol. In Mooncrash, playing only stealthily is impossible — you have to constantly switch characters, and only a couple of them are tailored to stealth gameplay (let alone the time limit, which is the worst enemy of the methodical hiding in shadows). Initially, I was disappointed that the game forced me to play out of style — but I grew to like it eventually. When I played the base Prey game, I didn’t invest in the vast majority of upgrades and abilities because I never needed them. In Mooncrash, I have to play as a tank, a hacker, a technician, and a psyonic abilities mastermind — and thus, I discovered and enjoyed so many different mechanics and systems I previously ignored in Prey.

All five playable characters in Mooncrash provide different gameplay styles and abilities.

In spite of all this procedural madness, Mooncrash is still a tightly designed, hand-crafted game. The levels might have different enemies, tools, or hazards each time you play — but they always have the same amount of story. Like in Prey, you spend much time reading emails and notes, listening to audiologs, digesting environmental storytelling, and uncovering the mysteries of this place, what happened here and why it all turned to hell. There are nice connections to the events of the base game. Having five different characters gave Arkane even more tools to tell the story of Mooncrash — every playable person is key to the events that took place on Pytheas, and you can encounter certain events from the points of view of different people.

Prey: Mooncrash is yet another reason why I admire Arkane so much. Instead of making just a couple more levels for a DLC, the team has completely reinvented the formula, while staying true to the core Prey experience. Instead of reinventing the formula just for the sake of reinventing it, Arkane deliberately played with systems — particularly procedural elements — that are obviously something that the design team is fascinated with, and wants to experiment with even more in the future. Thus, it’s not surprising in the slightest that the studio’s next game, Deathloop, appears to be heavily inspired by Mooncrash — multiple runs are at the core of it, and it is build around exploring and re-exploring the world that always changes and challenges you.

Deathloop appears to be built upon many mechanics Arkane pioneered in Mooncrash.

I’m fascinated to think how immersive sims can become even richer, even deeper, even more replayable and unique for every player by adopting more and more procedural elements, and I can’t wait to see where Arkane, and other developers, take the genre next. In the meantime, let me do another run around Pytheas — who knows if I can survive this time?

Other immersive sims related articles by me:

Prey: Mooncrash is the proof that procedural immersive sims can work

Written by Maxim S