Slave Zero X: Episode Enyo is a weird tie-in for a weird game: a free prequel Quake mod for the upcoming 2D character action game Slave Zero X, itself a prequel to the 1999 PC/Dreamcast mech game, Slave Zero. That context might make it seem impenetrable, but even if you're not already “Slave Zero-pilled” (sorry), the six-level Quake campaign is a solid little free FPS that's worth your time.

Episode Enyo casts you as one of Slave Zero X's main villains, and as a gunslinging assassin type, the titular Enyo is well suited to her own boomer shooter spinoff. Poppy Works and Ironwood Software did a great job of distinguishing this total conversion from base Quake, most impressively with a custom arsenal fully distinct from the original game.

We trade Quake's idiosyncratic collection of guns for a more classic Doom-y lineup (pistol, machine gun, shotgun, plasma rifle, etc.), but they all feel and look good, and it's the sort of above and beyond effort that would distinguish any Quake mod. The enemies consist of Quake's classic lineup, but reskinned with high-quality, more Slave Zero X-appropriate models: Death Knights become armored cybercops with riot shields, Scrags are automated drones, and the fearsome Shambler is disguised with a carapace of power armor that looks like it was smuggled out of the Fallout Enclave's dressing room.

We're coming dangerously close to reaching peak saturation of neon '80s epic cyberpunk stuff in games⁠—I never want to see that pink and teal sunset with palm trees over a grid horizon ever again⁠—but Episode Enyo benefits from its source material's grittier, grungier, '90s take on the genre. 

These city streets are really dirty and nasty (a perfect fit for Quake) with the requisite neon signs of Japanese characters making for a nice pop of color. Slave Zero X also has some neat bio-horror things going on, and some of the levels in Episode Enyo have these creepy, Giger-y statues and skyboxes I can really dig.

These are also solid boomer shooter levels that encourage exploration and secret hunting, with a lot of vertically-oriented areas, switchbacks, and even a few alternate routes. I don't think there's anything in the levels with the killer edge a retro FPS needs to really stand out these days⁠—Ultrakill's vertigo-inducing set pieces or Hrot's intricate detailing and sense of humor⁠—but I enjoyed my time in them.

Episode Enyo is a standout Quake campaign on its own, but its connection with Slave Zero X is really interesting. Having multiple games of different genres showing off the same setting helps it feel more expansive, and I always appreciate seeing things like Larian's oft-forgotten RTS, Divinity: Dragon Commander or adventure game Hypnospace Outlaw's FPS spinoff, Slayers X: Terminal Aftermath: Vengance of the Slayer.

Unlike those other quite good games, though, Episode Enyo's free, assuming you already own Quake. If you have Nightdive's remaster, you can just download Episode Enyo from the addons section of the main menu, but the mod will also work on the major source ports of O.G. Quake, with the project available for download on ModDB.

Slave Zero X itself, meanwhile, releases February 21. You can wishlist the game and check out its demo over on Steam