Developer Update #6 – The Campaign

This entry was supposed to be posted quite a while ago and look at the new enemy types, but they have been somewhat delayed due to both technical and health issues – so instead here’s a smaller update on the structure of the campaign!

Core Decay will launch as a singleplayer game with a semi-linear campaign. This keeps the project reasonably small in scope – although I would certainly love to expand upon the game with multiplayer capabilities post-release!

Levels in Core Decay

There are 11 levels planned for the initial release of the game. While I initially looked at procedurally generating level designs, I ultimately decided on a hand-crafted approach since it felt more in line with the old-school approach of the game and allows for more deliberate level design. To encourage replayability there is randomization in most other game elements, such as enemies and pickups encountered, the leveling system with randomized upgrades, and so on – but the levels themselves are static.

On the “Veteran” difficulty level, all randomized elements are completely disabled – for those who desire a fully old-school experience!

Level structure approaches

When deciding on how to actually structure up the levels, there were a few approaches to consider:

Levels follow each other in a completely linear fashion. Most older FPS games follow this pattern, and it has strong advantages in how it lets you ramp up difficulty and complexity in a well-designed manner, as well as progress the story naturally. It’s the worst of the approaches in replayability however and there is no player agency involved.

Locked branching
This approach has the campaign structured into phases, and within each phase the player can pick which level to play, locking the other choice out for that playthrough. This enhances replayability but means that twice as many levels have to be made for the same campaign length, and makes story progression more difficult.

Free branching
This is the same as the above, except unpicked levels are still played – the player simply gets the choice of which order to finish them within each phase.

Fully free
All the levels are accessible at once and the player can do them in any order. This offers the greatest player agency and replayability, but presents far more of a challenge in both storytelling and difficulty/complexity ramping.

The level structure in Core Decay

Ultimately I decided to go with a variant of the free branching approach. The campaign and its 11 levels are divided up into phases:

  • Phase 1: Consists of a single introductory level.
  • Phase 2: Consists of 4 levels which can be done in any order.
  • Phase 3: Consists of a single story-driven level.
  • Phase 4: Consists of 4 levels which can be done in any order.
  • Phase 5: Consists of the single final level.

Some in-level balancing also accounts for the fact that the player will be more powerful between levels as they gain equipment and level up – but the main jump in difficulty will be between phases.

The level select screen (work in progress, names obviously not final).

Since the levels themselves are set on facilities across Earth, levels are selected on a world map interface which also offers some opportunities for worldbuilding.

The narrative

Although there is a heavy story focus throughout the level, emphasis is still made to have this part subdued and mostly opt-in on account of the player. Those uninterested in the storyline will have an easy time not engaging with the vast majority of it.

For those who do wish the engage with the narrative, it is primarily conveyed through two parts – comlink conversations with a side character, and datalogs found throughout the levels. Some conversations – such as those between campaign phases – always appear, although are easy to skip through should the player desire. As for the story itself, I will cover this in a future dev update as much of it is still finalizing – but overall it will focus around themes of cybernetics, AI, human consciousness, corporatism and environmental decay. It’s pretty classic as far as dystopian sci-fi stories go, but should nonetheless prove somewhat interesting!

That’s all for now – the next dev update should hopefully be showing the new enemy types in greater detail!

Developer Update #5 – Leveling & Cybernetics

In this update we’ll take a closer look at how leveling works in Core Decay! The leveling system is an optional part of the game (disabled in the “old-school” difficulty level) but it significantly boosts replayability and is a lot of fun to engage with.

Experience & Levels

Experience points are rewarded for a few specific actions:

  • Defeating enemies (more specifically, picking up XP globules from killed enemies – these globules disappear after a short while).
  • Finding secret areas.
  • Finding XP pickups.
  • Successfully escaping the facility during meltdown.

Once you have gained enough XP, you level up. This does not make you inherently stronger in any way, but it does grant a single upgrade point.


Using an upgrade point – which you can do as soon as you level up or save it for later – presents you with a randomized selection of 3 cybernetic modules. If you don’t want any of the 3, there is also a fourth “Gamble” option which randomly gives you a different one without the ability to preview it first.

Cybernetic modules are passive perks that provide the player with a variety of benefits. They have no level requirement to show up, but some cybernetics require others to be unlocked first. They are also grouped by rarity, with rarer ones simply being less likely to show up:

  • Core: the majority of cybernetics belong to this rarity. They generally provide smaller or one-time bonuses.
  • Advanced: cybernetics of this rarity provide stronger bonuses. They are often upgraded versions of a Core cybernetic but there’s also plenty of unique ones.
  • Prime: cybernetics of this rarity are far less likely to appear but provide potentially game-changing abilities.
  • Experimental: This is a special rarity – experimental cybernetics are as likely to appear as Prime ones and generally grant even greater bonuses, but they all come with a drawback that makes picking them a careful decision.

The final version of the game is planned to have close to a hundred cybernetics. Here’s a few examples, note that most names are not final and will be replaced with more loreful alternatives:

Core Cybernetics

  • Transcendent: When respawning, you now start with full health instead of half.
  • Vitality: Increases your maximum life to 150 (from 100).
  • Rearm: Instantly refills your primary ammo.
  • Scholar: Increases XP gain by 10%.
  • Breather: Instantly destroys all nearby enemies.
  • Energy Leech: You gain energy ammunition when taking damage.
  • Module Regulator: Choose between 4 cybernetics instead of 3 when leveling up.
  • Hacker: You can now hack computer terminals to get location information of nearby enemies. Hacking takes 6 seconds during which you are vulnerable.
  • …and many more!

Advanced Cybernetics

  • Regeneration: While detected by an enemy, you regenerate 1 health per second.
  • Eye Scanner: All enemies now display health bars.
  • Health Leech: You gain a small amount of health by damaging enemies.
  • Spectral: You can move through enemies. While inside an enemy, weapons cannot be fired.
  • Nanite Injection: XP globules now heal you for a small amount.
  • Rebreather: You are immune to toxic gas.
  • Advanced Hacker: You can now hack computer terminals to disable nearby enemies. Hacking takes 4 seconds during which you are vulnerable.
  • …and many more!

Prime Cybernetics

  • Personal Shield: You gain a shield which can absorb damage and recharges automatically.
  • Final Stand: When taking damage that would otherwise kill you, you become invulnerable for 10 seconds and have unlimited ammo. After 10 seconds, you die.
  • Eye Scanner MKII: Enemies are now visible through walls.
  • Thorned: Enemies take damage when attacking you.
  • Master hacker: You can now hack computer terminals to make nearby enemies attack their allies. Hacking takes 2 seconds during which you are vulnerable.
  • …and many more!

Experimental Cybernetics

  • Synthetic Heart: Takes one life away, or reduces your health to 1 if you are on your last life – but gives you three instant levels!
  • Tesla Coils: Automatically damages any nearby enemies, but upon doing so also damages your armor. You will never take health damage from this.
  • Combustion: When respawning, an explosion kills or damages all nearby enemies, but you also respawn with less starting health.
  • …and many more!

You will note that some of these provide an instant, one-time bonus, whereas others are passive and will remain useful for the entirety of the game. The one-time cybernetics can be vital in turning the tide short-term, but it’s a careful balance of making sure you stay equipped with useful long-term upgrades as well.

Randomized vs. static upgrades

This particular approach to leveling and upgrades has been designed to provide a combination of replayability and player agency/customization, with an emphasis on the former.

For a while I was experimenting with a single static list of all upgrades, some locked by level, which the player could choose from each time they level up – similar to the approach used in the earlier Fallout games. While this does have the advantage of letting the player plan out their ‘build’ of cybernetics, there’s less replayability and seems to fit a bit worse into a fast-paced FPS where the leveling is more of a compliment than a huge mechanic.

Ultimately the randomization/rarity-based model means that you still have some agency (especially since some cybernetics require others) but mainly it’s about giving you a different experience each time you play the game.

The leveling system is enabled on the Normal and Elite difficulty levels. Since the leveling rewards are inherently based on chance, the system in its entirety is disabled on the Veteran difficulty which is designed to reduce randomization overall. This also makes Veteran feel more old-school and more reliant on level knowledge, which is by design – the Elite difficulty still provides a challenging experience with leveling enabled for those who prefer it.

Thanks for sticking with me on this very text-heavy developer update! Next week we’ll have a look at some new enemy types.

Developer Update #4 – The Roadmap

Update: Please not that the roadmap is somewhat outdated at this point. I’m still leaving it up for reference, but as of right now there is no specific target date for the public alpha release.

Welcome back to more frequent developer updates! Rather than go over specific game features, I want to take this opportunity to lay out a more detailed roadmap and path to the full release. I know this is highly appreciated by many, so I have spent some time detailing a schedule of game additions and releases.

The schedule is quite generous in terms of time since this is a one-man project and I’ll want to account for a variety of unexpected delays, but even so: any dates here are very much subject to change, and things may arrive later or earlier depending on external factors.

Fall 2019: Public Mobile Alpha

For the next several months, the main focus lies on finishing a playable mobile demo, with the primary purpose of gathering public feedback. This demo will feature two levels, a handful of enemies and weapons, and a vertical slice of the gameplay experience.

This demo will initially be available to Patreon backers – natively on Android, and on PC as a port of the mobile version (the full PC version will be available later during the beta stage.) A much as I would like to provide an iOS alpha as well, I currently lack the resources for this – definitely aiming to be able to do so for the beta though.


The remaining half of August will primarily focus on adding two additional weapons, both of which use all-new ammo types and will add some much-needed variety to combat:

  • The Coil Shotgun fires electric pellets and is highly effective at shorter ranges. While each individual pellet deals fairly low damage, the electric charge damages enemies over time as they are hit. It can be upgraded to make its pellets bounce off walls, or to fire a single electric arc turning it into a sustained fire weapon.
  • The Mine Layer fires small explosive charges that stick to enemies or solid surfaces. When hitting an enemy, they explode after a short delay. When hitting a solid surface they turn into proximity charges which explode once an enemy gets nearby. It can be upgraded to use EMP charges which has no area damage but disables enemies, or to turn the charges into tripwire emitters that link together – they cannot hit enemies directly but deal massive damage when used as a trap.


September is focusing almost entirely on new enemies. The floating Probe that has been shown in footage so far – while adequate for its role as cannon fodder – is definitely a fairly static and boring enemy to fight. This month will see the addition of a number of enemies of various behavior and engagement ranges for much more interesting combat. Here are a few examples – not all of these will be added by the alpha release:

  • The Compressor is a repurposed mining bot which uses its front-mounted mandibles as a powerful melee tool. While slow to move and turn, they can activate a movement boost to rapidly close up on an unsuspecting player.
  • The Mite is a small ground-based enemy that acts as a small mine on legs. It is the only enemy type that can follow the player into smaller ventilation ducts, and can crawl on walls and ceilings. A characteristic ticking sound makes it easier to tell they are nearby.
  • The Mite Nest is a slow-walking construct that periodically spawns enemy mites. Its own weapons are weak so it generally makes sense to prioritize it as soon as possible to avoid being overrun. When defeated it consumes itself in a powerful explosion.
  • The Immolator is a powerful enemy you will want to flank – in the front the Immolator is equipped with a powerful blast shield which has to be destroyed before it can take damage, whereas at the back it features an exposed fuel tank making it an easy target. Its armament is no less impressive: It features twin-mounted kerosene cannons that covers the player in a flammable material, followed by a smaller top-mounted igniter that sets the kerosene on fire and causes massive damage over time. Strategic players can trick the Immolator into covering other enemies in kerosene, and then ignite it with one of their own weapons.
  • The Drone is fast and airborne, and features a single-use missile launcher capable of dealing a moderate amount of damage. Each Drone is coupled with a rearming station, and after firing it has to return to be able to launch another missile. While fast, small and agile, a player can pursue it to its rearming station where it is vulnerable.


October is dedicated to finalizing two fully featured levels for inclusion in the playable alpha. With this there will also be a number of new environment props added, such as billboards and unique props. The following levels are planned for inclusion:

  • AR-1 Cryogenics– cybernetic experiments were undertaken in this Antarctic facility serving as the introductory level of the game.
  • Axiom Hub – this installation, alongside 47 others of the same design, was part of a massive project aiming at draining Earth’s oceans. It features underwater sections and some other unique design features.


This is where the first playable version of the game is made available! I am currently looking at releasing the playable alpha at some point in November – the weeks leading up to this will mostly consist of bug fixing, optimization, and refining existing features.

Winter 2019/2020: Feature Complete

The following months will focus on getting all the game features fully implemented. Many are in already, but some remain and will be added here:

  • A weapon upgrade system which lets you find Upgrade Kits and specialize your weapons with upgrades of your choosing.
  • Environment hazards: Acid (damages armor heavily, health somewhat), lava (damages armor somewhat, health heavily), poisonous gas (damages health directly, ignoring armor), and electricity (highly damaging but only if armor is empty).
  • Many more cybernetic upgrades! The game currently features about 30, but tons more are being planned.
  • Computer terminals – find story and lore datalogs, and disable/control enemies with the Hacking cybernetic module.
  • More enemies, weapons, and levels.

Spring 2020: Public Multiplatform Beta

At this stage I aim to roll out a public beta on all 3 target platforms (Android, iOS, PC) – still with only a handful of levels, but with the core mechanics and content much more fleshed out since the alpha version.

The public beta will be open to everyone, although Patreon supporters will get earlier access.

Late 2020: Content Complete & Release

The final release is currently being planned for late 2020 as a pay-once title without any in-game microtransactions. Any Patreon supporters of $5 or more will receive the game for free on all platforms!

Beyond: Post-launch support, expansion packs

Post-launch updates will be grouped into two categories – smaller patches and larger expansion packs. The former focus on bug fixes, balance changes, and quality-of-life improvements and will roll out as free updates, whereas expansion packs will be paid and provide a larger amount of new content. There are no concrete plans for exactly what these expansions will contain as I’m focusing on making the release version of the game everything I have envisioned.

Hopefully this provides some insight into the development schedule and process. As mentioned above these dates are still very much in fluctuation and with a one-person development process there are a lot of things that can cause delays, but nonetheless it’s a schedule to try to stick to!

Next week’s development update will detail the XP and leveling system, and the cybernetics/perks the player gain as they level up.

Developer Update #3 – The Reactor Core

Today we’ll have a look at the final part of any level – the reactor core battle! But first, let’s have a look at some of the overall improvements made this week.

Randomized pickups

Pickups are one-time consumables spread out in a level that give the player various bonuses, such as restoring health, armor or ammo, giving extra XP, temporarily increasing damage or speed, and so on. Rather than being static per level, pickups now randomize – with a table that makes sure more powerful pickups are less likely to appear. This makes each playthrough different and adds to variety when going through the same level multiple times.

On the Veteran difficulty level, which is aimed at making the game less based on luck and more old-school in nature for those who prefer that kind of experience, all pickup randomization is disabled (with the exception of pickup spawners, detailed below).

The game has 3 difficulty levels: Normal, Elite, and Veteran. Normal is the baseline experience while Elite makes combat more challenging and increases the punishment for dying. Veteran is more of an alternate version of Elite, which removes almost all randomization elements as well as the leveling system – it is an optional side mode which aims to make the game play closer to old-school FPS games.

The Pickup Spawner in action.

The Reactor Core Battle

The final objective of any level is to destroy its reactor core. The route there as well as the core chamber layout varies greatly from level to level, but nonetheless the overall goal remains the same. The core has 3 modes:

  • Dormant. The initial state – the player can freely enter the chamber and damage the core. Any spawners are inactive and the core turret cannot fire.
  • Lockdown. As soon as the core takes damage, it enters lockdown – the outer blast doors close so that the player cannot leave (and if the player dies they now respawn inside the chamber), the core deploys defensive shields and activates the turret, and any spawners are now enabled.
  • Meltdown. Once the core is destroyed, it goes into meltdown – all defenses are inactive and the blast doors are once again open, but the player only has a limited time to escape and find the emergency exit before the core explodes.

Below is an example of a smaller core chamber, and descriptions of everything it contains:

Blast doors

These exist at the entrance of the chamber and close as soon as the core enters lockdown – preventing the player from leaving until the core is destroyed.

Blast shield

This is positioned between the blast doors and core and block all projectiles. Its purpose is to make sure the player has entered the chamber before the core can take damage, so that they cannot run out as soon as lockdown begins.


This needs to be destroyed to progress, and is vulnerable as the player enters the chamber.

Core shields

These are initially inactive, but as soon as the core takes damage they deploy around it to protect it. They can be damaged and destroyed with player fire, and are segmented so that the player has to choose which area to take down first.

Core turret

This is also inactive until the core takes damage, but once started rotates around the core and fires at the player. The turret is invulnerable and unlike the player, it can fire straight through the core shields.


These cylindrical objects usually surround the core and provides the player with strategic cover. As the core takes damage, these gradually lower into the ground, until there eventually is no cover remaining.

Pickup spawners

To prevent the player from running out of ammo and to encourage moving around, ammo and other pickups randomly appear through pickup spawners around the chamber. Only half of the spawners can have a pickup simultaneously, so the player will need to be mobile and keep running between the spawners.

Enemy spawners

These spawners gradually create new enemies during lockdown, though only one at a time per spawner. Only the first spawned enemy provide the player with XP and score. They are not necessarily present in all chambers.

The Meltdown

Each level has an emergency exit – its location varies entirely depending on the level. Before the core has been destroyed the exit is locked down, but once the core enters meltdown the player needs to locate the exit (if they haven’t already) and enter it before a countdown timer runs out. If playing on the Normal difficulty level, you still proceed to the next level if you fail, although losing out on a large XP bonus and losing much of your equipment. On the Elite difficulty and above, the player loses a life and restarts the level – so successfully locating the exit before destroying the core is highly recommended!

As a side note, if you want a better explanation of how the player survives even if failing to escape the meltdown in time (aside from “That’s how Descent did it!”), it is covered in the storyline and will make a lot of sense!

Next time

There will be a one-week hiatus of developer updates – the next update will be on August 11th, focusing on laying out a detailed roadmap of the work to come and target release period.

Developer Update #2 – Movement & Combat

Not a whole lot of news this week as I’ve been on vacation, but here’s a recap of the recent progress, and a more in-depth look at how Core Decay handles player movement.

Advanced movement controls

Core Decay features a Doom-style movement scheme – that is, you move and turn at the same time on a single axis, you cannot look vertically, and there is no strafing.

The reason for this is (apart from a little bit of nostalgia!) is for the game to be highly playable on mobile. Generally, mobile FPS games are quite clunky to control since you have to manage three things at once: moving, looking, and performing actions (e.g. shooting) – while generally only using two fingers. As a result you have to stop and aim and then fire, which makes combat feel much less fluid.

With movement and looking all on a single joystick, this lets you fire, crouch, switch weapons and more all while moving. While this generally works well and combat does indeed feel quite fluid, some of you commented on really wanting the ability to strafe and turn more quickly. This is great and valid feedback, and so I implemented a solution that should hopefully feel great to use while still keeping the simplicity of the original movement scheme.

Specifically, next to the fire button there are now four buttons:

  • Quick strafe left: This makes you quickly dodge sideways to the left.
  • Quick strafe right: This makes you quickly dodge sideways to the right.
  • Crouch: This toggles crouching (used for exploration more so than for combat).
  • Quick turn: This makes you quickly turn 180 degrees.

Using these buttons, you can quickly move sideways and turn around quickly, while being able to keep the regular turn speed somewhat low for precise aiming. There is still some testing needed to tweak all the various speeds, and I’ll probably want to add a (tiny) cooldown to the strafing to prevent exploits, but in general it works quite well!

On PC, the game will adapt a modern control scheme with full mouse look and WASD controls, as there is far less reason to stick to a Doom-style scheme with a mouse and keyboard. As the UI will look different there is also no fire button or advanced movement controls, as they are all covered by standard FPS keyboard and mouse actions.

Head bobbing

There is now considerate head bobbing while walking (thanks @_stroopwaffle for the suggestion!), which makes a huge difference to how the game feels to play as you move around. Movement should now be less floaty and have more weight to it – note the difference compared to the first movement video which has no bobbing!


In addition to the above, I have started implementation of spawning stations.

Enemy spawners

These new stations spawn enemies when the player is close by, and cannot be destroyed. Spawned enemies give out no XP or score, so activating a spawner should be avoided at all costs – the only exception is if you have a currently active perk that grants bonuses for destroying enemies, which still count.

Spawners predominantly exist alongside reactor cores where they spawn enemies continuously during a lockdown, but can also be found within the rest of a level where they work based on proximity.

Ammo spawners

Like enemy spawners, these stations also spawn something continuously – in this case, ammo pickups. They exist exclusively next to reactor cores where they act to prevent the player from running out of ammunition during a reactor fight (more on the mechanics on reactor fights in a later dev update).

Next time

The next dev update will feature an in-depth look at the core battle mechanics! Hopefully the spawning stations should be all done by then as well, which will give a great opportunity to demonstrate the entire core battle gameplay loop.