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.

Patreon page is now live!

If you are interested in contributing to the development of Core Decay, check out the Patreon page linked below. Any contributions are appreciated! Also feel free to share ideas on how I can give the best possible value to Patreon supporters – while a closed alpha is still some time away, if there is anything else any of you would like to see, don’t hesitate to let me know.

Developer Update #1 – The Vision

Welcome to the Core Decay devblog! Since this is the first developer update, I figured I’d start off with the background behind the game and what the general goals of the project are.

Core Decay is a one-man project and a celebration of the DOS games of the late 90s. Growing up with games such as Quake, Descent and Doom, I wanted to return to this era – in particular on mobile devices, since aside from a few ports of PC games there is not really any way to experience this genre on mobile right now.

Base Mechanics

Screenshot of starting level.
The beginning of the game, designed to convey the amount of player choice present.

The game itself is a first-person shooter in an industrial sci-fi setting, where the goal of the player is to progress through 11 distinct levels (with some choice regarding level order), finding and destroying the reactor core in each facility before moving onward. Levels consist of several sectors of varying security, and the player has to find appropriate keycards to progress. Once the reactor core is located and destroyed, there is a limited time to find the escape exit before the facility is obliterated.

Although the main gameplay loop is highly rooted in classic shooters, there are a few more modern elements as well. Core Decay features a leveling system where each time the player levels up they get to pick from a random selection of unique perks, each granting some sort of bonus or benefit. This adds to replayability and makes every playthrough more unique.

The Art

The Power Saw, the starting melee weapon.

With Core Decay I wish to recreate not necessarily full-blown pixel art but more of a “DOS-era” aesthetic. Blocky geometry, un-smoothed textures, a MIDI-style soundtrack and a darker visual tone all contribute to this and should result in an experience much like the 90s PC games it draws its inspiration from. In addition to this there are some more modern features incorporated to add extra detail – ambient occlusion, bloom, lens flare and CA comes to mind – but all of these can also be turned off if you prefer a more “authentic” look.

Ultimately I’m hoping to have the various facilities quite visually distinct from each other. The facilities explored by the player stretch across the world, and a storage site in the Arctic should after all feel quite different from a biological research lab in South Africa! While all levels are indoor-only, there are still plenty of ways to convey a different location such as unique props and color grading.

The World

Core Decay takes place across a series of mysterious facilities across Earth – they are somehow all connected to a world-altering design, and the game plot focuses on uncovering the nature behind these sites and whoever has been behind creating them. The game explores themes of post-humanism, cybernetic augmentation, environmental disaster and corporate power.

Mission selection world map.
The player can choose which mission to play next!

The degree to which the player interacts with the storyline and world is very much up to the player. Datalogs and NPC dialogues provides an in-depth look at the story and lore of the game, but can also be entirely ignored if more interested in the gameplay.

Platforms & Distribution

The current plan is to first release the game on mobile platforms, with a PC version to follow. On mobile platforms, the game will be a single $5 purchase with no micro-transactions, allowing the game to be designed with all the old-school style of mechanics intact.

Schedule & Roadmap

In the interest of transparency, be aware that the game is currently in pre-alpha and is still a long way from being complete. Any contributions help making the development time shorter and are hugely appreciated, but much remains to be done and a public beta is quite far away. As I am a sole developer it is also difficult to provide an accurate development roadmap, but it is still my goal to get one out as soon as possible. Thanks for understanding!

What’s Next

The reactor core.
The reactor is the final goal of any level, though the design varies from site to site.

I’ll be aiming for weekly dev updates, giving an in-depth look at what is being worked on at the moment. As the game is so early in development many interesting design choices remain to be resolved, and hopefully this will make for some exciting updates. Until next time!