Roguelikes are a well-established part of the PC gaming landscape, with procedural gameplay, permadeath, and an eye-watering level of difficulty all key elements of the genre’s DNA. But what happens when you take those ideas and implement them in a six degree of freedom (or ‘6DoF’) shooter?
Answer: You get Sublevel Zero, which I had a chance to check out at PAX. I also talked with Luke Thompson, co-founder and lead programmer at Sigtrap, about how procedural gameplay will keep bringing players coming back, and the challenges of implementing procedural design in a 6DoF game.
For those who never had a chance to play Descent—the forefather of 6DoF—this style of game may not be instantly familiar. In Sublevel Zero you pilot a ship from a first-person perspective, exploring an intricate, almost-claustrophobic complex, finding keys and battling enemies in search of a reactor to destroy at the level’s end. But this is no trad ship sim—you can move up, down, left, right and backwards just as easily as you can thrust forwards. Think of it like controlling a helicopter with benefits.
“There’s a few key difficulties for procedural generation in this kind of game,” Thompson explained after my first playthrough. “It’s tricky when you take something from two dimensions to three, and when I say three dimensions I don’t just mean like a first person-shooter. I mean something where the Z-axis is exactly as important as the X and Y-axis.”
“One of the things we do as levels go on, and you’re further into the campaign, is the up-and-down gameplay increases. The map will tend to be flatter earlier on, to give you more of a chance to get used to the controls, then get more complex as your understanding increases. Over time you really do develop a spatial awareness.”
Which is something I can attest to even after playing and dying a handful of times. The controls—which enabled me to twitchily move around any direction, while still maintaining the sense of weight and momentum you’d expect from piloting a large vessel—came easily by the time I was on my second playthrough. More importantly, my awareness of where I was in relation to everything around me had also drastically improved.
Thompson explained how the procedural systems generate levels: “We’ve got this concept of the critical path [that] goes from the beginning of the level to its end, and there’s always going to be side paths built around [this main path]. On the critical path enemy difficulty increases linearly, but outside it the system will generate enemies that are more difficult, to guard more powerful unlockable weapons and crafting items than those you’ll find on the main path.”
I wasn’t exactly sure when I was on the critical path versus when I’d strayed off the beaten track, but I did find a variety of different weapons and items for crafting, from missiles large and small, to machine guns, and various laser rifles, each with their own ammunition and associated tactics. Though I wasn’t able to craft a weapon from the items I had found during the demo, you’ll need to find weapon components, with different stats, and spend a found resource called nanites to combine them.
My expanding arsenal helped when I started running out of ammo for my initial guns, and was forced to switch up loadouts on the fly. Thompson said that they wanted to implement ammunition scarcity, both to ensure players kept trying new weapons, as well as to make sure the tension was ratcheted up.
It works. By the end of my demo I was frantically dodging and weaving through the gunfire and charging melee attacks from the various enemy types, forcing myself to quickly change weapons and strategies as my health and ammo counters rapidly approached zero. Health powerups did exist, but they were sparse.
There will be dozens of guns available in Sublevel Zero, all of which will be available to find and craft, through subsequent playthroughs, once they’re initially unlocked. The real trick in a roguelike, according to Thompson, is making sure that these unlockable weapons aren’t just more powerful than those you start with, but rather come with their own unique strengths and weaknesses. Since every death starts the player back at the beginning, Thompson believes that the knowledge of having unlocked these special weapons, and the desire to try out the new approaches they enable, will keep players returning.
Sublevel Zero is currently slated for an October release, and feels like it’ll finally scratch that Descent itch many of us have suffered with for decades now. The demo was certainly a challenge, and I never managed to find the reactor I was looking for, but I can’t wait to dive back in and try again.