This is Core Decay

Welcome to the first dev blog entry for Core Decay! I’m Ivar Hill and I’m the Game Director of the project – those of you who have followed its development for a while will know me as having worked on Core Decay as a solo project for a number of years!

Core Decay is, at its heart, a love letter to the immersive sims of the late 90s and early 2000s. As with games such as Deus Ex or System Shock, it places a heavy emphasis on presenting an intriguing setting, with a focus on open-ended exploration, immersion, and discovery.

As is a staple in the genre, it also makes for a soapbox to explore philosophical ideas – Core Decay’s story centers heavily around the nature of consciousness and humanity, and how in a desperation to survive we may find these ideas to be more mutable than we’d think.


Core Decay takes place in 2089 – this is a time of great desperation, as near-unlivable environmental conditions and shortages of vital resources have led to major societal shifts. Although – perhaps surprisingly – the world has been spared from larger military conflicts, society at large sees itself simply trying to survive year by year as living conditions are only getting worse.

Unbeknownst to the general public, things are even worse than they seem, and the Earth is about to reach an entirely non-survivable state much sooner than anticipated. There are, however, those who know – and this group of individuals is set to sacrifice everything to make sure that humanity can keep on surviving even when all else is lost.

It is in this world of despair that you awaken, unsure of who you are or what led you to the place you find yourself in – and throughout the game you will go on a great journey of discovery spanning five continents.

Level Design

The game is structured into ten locations across the Earth – each a large area to explore with its own narrative and atmosphere, and all part of the game’s larger storyline. Although Core Decay does not feature large hubs as such (akin to Deus Ex), most of the locations of the game are not entirely hostile – there will be people to talk to and many non-combat areas and approaches.

As with any immersive sim, the most significant focus of the game is offering you many ways to resolve objectives, with exploration and creativity being just as viable of a way forward as engaging in combat – often even more so!

The City Of Seversk

As an example, an early game level features an enclosed facility that you have to enter. This facility is located in Seversk, Siberia, and the heat and water it generates has attracted a small group of survivors who have made an encampment next to it, finding a way to survive even in the harshness of the Siberian winters.

This settlement of survivors, led by a previous facility employee named Mikhail, has been plagued by problems. Radiation leaking out of the plant is slowly poisoning the inhabitants. Furthermore, the facility water lines have been cut off leaving the settlement with no continuous source of water, and their stockpiles are running low.

To make matters even worse, friction within the settlement reached a breaking point – although Mikhail attempted to take a humanist approach and distribute the limited resources according to who needs them most, not everyone feels the same. In a dispute, a smaller group of people argued for a survival-of-the-fittest approach, and although not able to stage a full scale mutiny they nonetheless split up and formed their own smaller camp nearby.

Talking to Mikhail, he asks you for three favors. One is to re-establish the water connection to the facility, and therefore the settlement. The second is to approach the splinter group and convince them to rejoin the larger group, as he fears – rightfully – that they are staging a violent takeover. The third is to find a way to stop the radioactive emissions from slowly killing the settlement inhabitants.

If you approach the splinter group, their leader has an alternate suggestion – poison the water line connecting to the larger settlement, allowing them to move in and claim the resources for themselves.

Dealing with the water situation – or the survivors at large – is optional, but if you choose to do so, you have multiple ways to handle it. The water line can be fixed, which will gain Mikhail’s gratitude. Alternatively, you can poison the lines leading to the larger settlement – or just personally kill everyone within – which will let the splinter group move in, and let you retrieve facility access as a result. Finally, you can also poison both water lines, killing off all human survivors altogether.

If you choose the first option, the splinter group can also be dealt with. You can talk them into joining the larger settlement again by changing their viewpoints, which will make Mikhail very grateful – although it’s a difficult task. You can also convince the group to leave altogether, a less optimal solution but still pleasing Mikhail. Finally you can simply kill the splinter group, earning Mikhail’s disapproval unless sufficiently argued for in a later conversation with him.

In addition to all these various options, you can also engage either settlement in direct combat. Although very challenging it’s still possible to simply kill all the survivors, also gaining facility access as a result.

And as mentioned earlier, all of this is entirely optional, as this is just one among many ways to get into this facility!

Design Philosophy

From a broader design standpoint, Core Decay is developed with a focus on verisimilitude – or in other words, things should behave or present themselves in the way you logically expect them to. This doesn’t necessarily mean realism, though given the game’s near-future setting there’s definitely some overlap. A few examples of how this manifests itself in practice:

  • There are many areas of game levels which serve no specific gameplay or design purpose, but rather make sense in terms of how the location might have been constructed from a lore standpoint.
  • In-world pickups are placed in locations that make logical sense, rather than being arbitrary. A person who barricaded themselves into a room might have put ammunition in it, whereas an IT office might contain bypass tools.
  • There is no real-time map on the HUD. Rather, you might see maps on screens in the level, or be sent images over your comlink that you can look at for reference.
  • Doors that look like they could be destroyed with explosives, can be.
  • The game always explains or makes logically clear how you have reached a certain destination.
  • Avoiding enemies is a perfectly viable way to proceed – even ones important to the story.
  • Log entries usually comment on the world around them. A room is unexpectedly flooded? The nearby terminal probably mentions it, unless it happened after an evacuation.
  • Humor within the game is based on the personalities of whoever wrote emails/chats/log entries that you encounter. If whoever wrote a log entry has a certain sense of humor, that is reflected in their individual entries. If they are the serious type, that sets a different tone.
  • If you lose a leg, you move slower. If you lose both legs, you have to crawl until healed.

As can be seen in the above examples, this design philosophy is distinctly different from a gameplay-first approach. Rather than design around specific gameplay mechanics and have all other aspects follow – a methodology that works fantastically well for many subgenres of shooters! – in this case the focal point is the worldbuilding, narrative, and atmosphere. An approach that, I hope most will agree, is very suitable for a story-focused immersive sim 🙂

Gameplay Mechanics

Regardless, in terms of actual mechanics there’s many ways you can interact with the game world, all serving to provide you with a wide range of options at any given time.

Combat is usually a viable approach, although not necessarily the easiest or most straightforward one – the world around you is very dangerous and being selective about when to take the risk of engaging in combat is wise. At your disposal is a wide range of weapons (both lethal and non-lethal), as well as many ways to upgrade and enhance your combat ability.

Actual management of weapons and other equipment is done through a grid-based inventory, requiring you to strategically decide which equipment you want to keep throughout the game, balancing your available resources with your playstyle.

Apart from weapons and equipment, you can also install cybernetic implants into your body which has both combat and non-combat benefits. All cybernetic implants are passive in nature but can provide significant abilities! Run faster, jump higher, see through walls – the opportunities are endless!

It is not just dealing damage that has a lot of depth to it, however – taking damage does as well! When taking damage, it is absorbed by one or several of seven regions: your cranium, torso, abdomen, left arm, right arm, left leg, and right leg. Different sources of damage may spread differently – for instance, breathing in toxic gas mainly damages your torso, and falling from high heights mainly damages your legs. Once damaged, a body part may give you certain penalties until healed, and if entirely incapacitated you can suffer some quite drastic downsides!

There are also many objects around the world to interact with – most notably, computer terminals and PDAs which may contain interesting information or means to control various parts of the level. These also often provide a window into the lives of various inhabitants of the places you visit.

Apart from combat and exploration, the game also features stealth elements (though it’s worth noting that it is not primarily a stealth game – non-combat approach more often involves finding ways to avoid even getting close to hostiles!) as well as a dialogue system where you can talk to people (or non-people…) that you come across.

Closing thoughts

We have of course only scratched the surface of Core Decay within this post, but nonetheless I hope it may have shed some light on what this game is trying to be and what you might expect out of it! Some closing notes:

This is not Deus Ex 5

…having spent a couple thousand hours playing the Deus Ex series, I wish! 🙂

But no, in seriousness, I do want to make a point that despite drawing a lot of inspiration from games such as Deus Ex or System Shock, Core Decay is still very much its own thing. It is in the spirit of these classics but there’s a ton of things it does very differently – the last thing I’d want is for anyone to feel their expectations are not met. However, let me say this with great confidence: If you do enjoy Deus Ex or System Shock, there’s very much to enjoy for you in this game!

The game is early in development

I also want to iterate something I’ve mentioned in various places over the last few months – Core Decay is still very early in development! There’s a lot left to be done, so I’d recommend setting your expectations on a release date accordingly 🙂

Next on the dev blog

Future dev blog posts will be much more “behind the scenes”-like and show more insights into the development process. I wanted to make sure to present the game a bit closer first, but expect to see things like level design, coding and art sneak peeks as we move forward!If you have any thoughts or questions, you’re very welcome to head over to the 3DR Discord server – – where there is a dedicated Core Decay channel. Thank you all for your time, and see you in the next update! Je pense, donc je suis.