Necromantic bullet hell CODEX MORTIS has rolled out its new Mutations update, and it is not exactly messing about. The Early Access roguelite launched on Steam on March 26, and Steam currently shows it sitting on 83% positive user reviews from 43 Steam purchasers, with a 20% discount running until June 4.
That is a decent place to be for a game that is still very much in the thick of Early Access, especially one this openly built around constant tinkering. The official Steam page pitches CODEX MORTIS as a necromantic survival bullet hell with solo play and shared or split-screen co-op, while the developers’ Early Access notes say they expect to keep shaping it with community feedback over roughly six months.
The big new hook is 249 spell mutations
The headline addition here is Mutations, which sit on top of existing spells and change how they behave rather than simply nudging numbers upward. According to the new update post, the system launches with 249 mutations spread across 31 skills, altering projectile patterns, area-of-effect shapes, summon types and aura behaviour. In other words, this is less “your spell now does 6% more damage” and more “your entire build has started behaving strangely in a crypt somewhere.”
The examples the developers give paint a pretty clear picture. Bone Spear, for instance, can be turned into a cone burst or an eight-spear nova around the player, while other skills are being pushed into different roles entirely. That sort of system should do a lot for replay value, especially in a game already built around stacking dark magic schools together and hoping your screen remains readable by the end of a run.
The level-up system has been rebuilt around it
The patch does not stop at new spell behaviour either. The developers say the level-up flow has been rebuilt so progression feels more like shaping a composition than mindlessly grabbing whatever card happens to appear. Earlier update notes had already signalled this direction, with rarity affecting how many upgrades sit on a card, milestone levels granting mutations, and the old spell level cap being removed.
That is probably the smarter change long term. Big content updates are great, but if the structure underneath them is flimsy, all you really get is more ways to break the same system. Reworking progression so builds feel more distinct from run to run is the sort of thing that can keep a game alive rather than just briefly louder. That reading is an inference from the patch notes and the earlier design goals the team shared.
It is still leaning hard into chaos, but not sloppy chaos
CODEX MORTIS is built around combining five schools of dark magic, commanding undead minions, and pushing synergistic builds across eight Early Access levels. The Steam page also highlights shared or split-screen co-op, 96 achievements, and support for 28 languages, including English, French, Japanese and more, which is not bad going for a game still in active development.
The patch cadence has also been pretty brisk. Steam’s official news feed shows a steady run of April updates leading into this one, including new spells, summoning tweaks, meta-progression updates, animation work and bug fixes before the mutator system landed properly today.
The AI-driven angle is still part of the conversation
There is also the bit people are likely to keep side-eyeing: the Steam page describes CODEX MORTIS as having “100% AI-driven development,” and the Early Access section says the team is using AI to iterate quickly on content and changes. Whether that is a fascinating experiment or a massive red flag is still going to depend very heavily on who you ask.
What is harder to argue with is that the team seems to be updating the thing at a pretty aggressive pace. If nothing else, CODEX MORTIS looks committed to the bit. Whether that makes it a clever Early Access curiosity or something more lasting will depend on how well all this constant mutation settles into a game people actually want to keep returning to. Steam’s current review score suggests a fair few already do.
Our take on CODEX MORTIS
This is the kind of Early Access story that is at least interesting. Not because every patch deserves a standing ovation, but because CODEX MORTIS seems determined to keep fiddling with its own guts instead of pretending it arrived fully formed. A system like Mutations has a much better chance of mattering than a throwaway content bump, and if it genuinely makes runs feel weirder, sharper and more build-specific, then this could be one of those updates that gives the game a proper second wind.
Looking for more news posts like this CODEX MORTIS one? Head over to our news section.
