A game by Sunteam for PC, originally released in 2019.
Grelox stars the titular character on a mission to save the planet of Aeon from a nefarious crime lord named Lady Mandrill. Mandrill's minions have been burrowing below the surface of the planet in search of some powerful ancient device. Grelox is a gun-for-hire with a passion for justice, so she sets down on the planet and dives into the tunnels, fighting enemies, unlocking passageways, and hunting for keycards to shut down each of Lady Mandrill’s subterranean lairs.

When the game begins, Grelox is standing outside her ship and she is able to enter either of two openings, which lead to the levels below. Completing both of these levels unlocks the next pair, and so on, across six levels that are divided into unique themes, ranging from high-tech to cavernous to organic. The seventh and final level is a straightforward action sequence through a grotesque Abadoxian environment packed with enemies.

The first six levels are comprised of a series of interconnected rooms that allow for backtracking and a bit of nonlinear exploration. Most rooms are gated off by doorways that can only be opened by hacking the computer terminals in the room. This is done similarly to the searching sequences in Impossible Mission, with a meter showing the player’s progress toward completing the hack. Enemies remain active during this time, so players must take care to eliminate nearby threats, and time their hacking to avoid invulnerable patrolling foes.

The game offers three difficulty settings, which determine how much health you have when you start each level. The player starts with five units of health on Normal, 10 on Easy, and a whopping 15 on Beginner. The player’s starting health is important because there is no way to restore health within the levels, and getting killed requires the player to start them over from scratch. Furthermore, there is no save function, so players must complete the game in a single sitting, but the game does offer infinite continues. Oh, and getting killed causes Grelox’s armor to explode, revealing a brief bikini shot before she is ejected from the level, which is a nod to the Metroid series’ similarly-clad heroine.

Grelox has a 2x variable jump, the ability to duck, and a short-range melee attack that she can execute to the left or right. Her limited range means that she must get up close to enemies, most of which are mobile, and most take two or three hits to destroy. There’s a bit of a glitch when jumping while attacking, as you can only attack once while ascending but you can attack again – even multiple times – when you begin falling back down. This can sometimes make the controls feel unresponsive when attempting to quickly perform attacks in the air.

Your limited health and offensive abilities make it doubly important that you dodge roving enemies, duck under laser blasts, and avoid incoming projectiles. Some enemies can be difficult to reach with your short-range attack, particularly if they are above or below you, so you’ll often find yourself waiting for enemies to position themselves properly so you can hop up or drop down to reach them.

Most enemies follow a simple horizontal patrol route, but some fly freely around the room. Killing enemies is entirely optional, but levels are generally designed in such a way that you must move around the entirety of any given room in order to traverse the area or reach all of the computer terminals. There are also indestructible hazards in some areas, and these include mines (which are sometimes hard to spot on the floor), turrets that activate when you get close to them, and roving spiked robots. There are even invulnerable versions of some enemies, as denoted by their silver color, but some of these color variations are subtle and don’t stand out.

Each area contains two keycards, which are required to open the door at the end of the level and destroy the device within. However, the game offers no map and no indication of which path leads to the final door versus those that lead to keycards. As such, you’ll need to feel your way through each level and make note of alternate paths. Enemies respawn if you leave a room and return (but unlocked doors remain open), which adds a layer of danger to backtracking.

Choosing the wrong path may get you killed as you backtrack to find the right path forward, and the game is built around using your previous failures to inform your next attempt. That said, levels aren’t terribly long, and once you know the proper route, you’ll be able to complete them more quickly.

Aesthetically, the game offers bright colors, a garish palette, chunky graphics, and glorious explosions that give it the overall appearance of a late-era DOS title, although the color palette is a nod to the Sega Master System specifically. Each region has unique tilesets and color schemes to give them a different feel. The game also features some nice synthy music, but it doesn’t loop naturally, so occasionally a song will fade to silence in the middle of a level and then start up again.

Grelox was developed and released as freeware by Sunteam, a studio based in the UK and headed by Paul Weller, who was responsible for the game’s design, art, and programming. Music for the game was composed by Galgox. The game was created using GameMaker Studio, and was inspired by Zillion on the Sega Master System.