Fill the Marathon-shaped hole in your life with Supplice, the best prog-heavy boomer shooter you've never heard of

It doesn't take a rampant AI super-intelligence to notice that Sony's State Of Play showcase last night had a conspicuous absence: Bungie's extraction-shooter reboot of classic FPS series Marathon, which recently landed in hot water thanks to much of its striking new aesthetic being directly plagiarized. Those disappointed in Bungie (or just wanting something closer in spirit to the classic Marathon trilogy) shouldn't sleep on Supplice over on Steam—French for 'Torture' and a personal early access favourite—which just rolled out its spicy fourth episode.

For those unfamiliar (and I can't blame you, the game has flown under the radar), Supplice wears its Marathon inspirations proudly. On top of being a fast, aggressive retro FPS with an incredibly beefy shotgun, it also punctuates its downright labyrinthine levels (expect to consult your map screen regularly) with exposition-filled terminals, often delivering several pages of well-written prose at a time.

While I love the combat here, it was the writing that really surprised me. It touches on a lot of the same territory as Marathon—an off-world colony under alien attack, with several AI constructs leading you from objective to objective—but puts a modern spin on some of the concepts.

The AIs here are less aspiring godheads and more malfunctioning black boxes, full of quirks and flaws inherited from their training data, inspired by contemporary (and frequently awful) water-guzzling chatbots. What might initially seem like malice often turns out to be the AIs just being a little bit shit.

The game also has an absolutely fantastic prog-metal soundtrack full of self-indulgent guitar noodling and even some positively soulful sax solos. It makes for a weirdly soothing alternative to the djent-heavy stylings of other games in the sphere, and it's honestly great to listen to outside of the game.

The new episode (the fantastically titled 'An Anthem of Hammers') has an overheated industrial aesthetic. Lots of reds, oranges and pools of molten metal and rock to test out the new heat-proof Lava Suit. There's five new enemy types, a new boss, another weapon (the Fission Dynamo) and a couple new pickups, and of course a big chunk of new story delivered through terminal screens.

By the time Supplice leaves early access, it's going to have a huge roster of monsters and texture sets for mappers to pick from, and the game running on the venerable GZDoom engine means that it shouldn't take much for those familiar with Doom level creation to make the hop. Given a bit of luck and a following wind, I can see this one growing for years.

There's still a good chunk of Supplice yet to come, with developer Mekworx (a small crew of veteran Doom modders) aiming for the full game to span a lengthy six episodes. But even with just the first four, you're getting plenty of bang for your buck, as the game is currently discounted to $10 (£8) on Steam.

For those really hungry for FPS violence, Supplice is also available in a further-discounted bundle with another favourite boomshoot of mine, the tetanus-tinged, grimy Quake-like Incision, which is graduating from early access in August. Well worth the £13 they're going for together, as both will eventually be going up in price.