For gamers of a certain age, the name “3D Realms” conjures up some fond memories. It’s the studio behind some of the classic first-person shooters that pioneered many of the conventions of 3D gaming that are still in use today, publishing games like Duke Nukem and Shadow Warrior.

Duke himself has long since moved on to greener (and bloodier) pastures with Gearbox Software, but the company itself, now owned by Danish investors, is making a true throwback game called Ion Maiden, powered by the 20-year-old Build engine.

In another bit of retro nostalgia, the game is also being released on a floppy disk — kind of. The Ion Maiden storage requirements are relatively modest at 100MB, but that’s still much more than a 1.44MB disk from the ‘90s could hold.

We’re releasing Ion Maiden on floppies with a twist! :) pic.twitter.com/CxRpNYzDLB

— 3D Realms (@3DRealms) April 13, 2018

In an unveiling video on its Twitter feed, the studio reveals how it accomplished this feat. By moving the shutter on the top of the disk, you can see it conceals a hidden flash drive.

There’s no word on when this special version will be available or how much it will cost, but it’s a clever bit of marketing for old-school gamers who remember switching to the B: drive to install MS-DOS games. The game will actually run on a 486 computer with four megabytes of memory.

In the game itself, you play as a Global Defense Force soldier named Shelly “Bombshell” Harrison, battling a cybernetic army. “Ion Maiden is a throwback to classic shooters, a spiritual successor to Duke Nukem 3D,” Frederik Schreiber of 3D Realms told GamesBeat. “It doesn’t impersonate a ’90s game. It is a ’90s game.”

There’s lots of blood and gore and an arsenal of weapons, including Shelly’s signature revolver “Loverboy.” The pixelated artwork is hand-drawn, and the game featured hundreds of Easter eggs and references to past generations of games.

“We wanted to make it as authentic as possible, but we didn’t want to limit it to the 1990s,” Schreiber explained. “[3D Realms founder] Scott Miller told us that this game should feel like it was built in Texas in the 1990s. It will have a classically illustrated cover.”

Ion Maiden is actually a sequel to a 2015 top-down shooter called Bombshell. That game was originally envisioned as a true Duke Nukem reboot until Gearbox reminded them with a lawsuit that they no longer owned the rights to Duke as a result of the Duke Nukem Forever fiasco.

Ion Maiden is already available in Early Access on Steam, and the initial reviews are very positive. The retail version of the game (including, perhaps, the floppy disk itself) will be out in fall of 2018.