Banjo-Kazooie. Ratchet & Clank. Jak and Daxter. Yooka-Laylee. You can learn a lot about 3D platformers by looking at the symbiotic beings at their head. In each of these games, the intertwining of two characters is made to look not like a ragdoll disaster but the most natural thing in the world. The gold standard for the genre is to make the complex look effortless – a hugely intimidating prospect for any industry newcomers hoping to imitate their favourites.
That hasn’t put off the team behind Billie Bust Up, who moved on from the Unreal Development Kit they used as students to Unreal Engine 4, the same tool used by many of their big-budget peers. Since then, they’ve applied the lessons of the programmers and animators who came before them in pursuit of that tricky end goal – the sense of freedom that defines the 3D platformer.
There are genres in which you can forgive a certain clunkiness. In the decade after 3D became the standard, RPG fans came to accept that real-time combat was not the forte of their favoured field.
But in the 3D platformer, there’s no room for that kind of forgiveness – the game lives or dies based entirely on how good it feels. Mario 64 is about the joy of movement, and if Mario himself was no joy to control it’d be about nothing at all.
The elusive ‘feel’
To begin work on Billie Bust Up, the team stuck its interlinked goat and fox in a blank room – adding mechanics one after the other, and designing platforms only once each fundamental element felt right.
“I think the tricky thing was trying to get the mechanics down because for a 3D platformer you want the game to be responsive and easy to control,” lead programmer James Thomas tells us. “We wanted it to be extremely fun to play. But one of the things we were aiming for was for the game to be fun in an empty level. We do have some bugs in this and we’re still in the prototype phase, but if you can have fun just moving around and jumping and that’s good, then we can introduce the mechanics.”
If you can have fun just moving around an empty room, then we can introduce the mechanics
Adding to the game piece by piece has made it easier to identify problems. The team noticed that adding certain mechanics to the game immediately made it less fun and resolved to iterate on them early. The ability to switch between Billie and Oscar, for instance, required a couple of days’ tuning. What’s more, the decision to give the characters an umbrella they could use to drift across gaps temporarily broke the game – the tool simply carried players too far, until the team introduced a drop-off effect.
Early playtesting, too, has undoubtedly helped highlight some of these hiccups that hampered the ‘feel’ of Billie Bust Up. Backers of the Billie Bust Up Patreon get to test the game early, and the team get feedback on “what feels good, what could be different, and what needs more work.”
“We just iterate,” Thomas says. “But the benefit of Unreal Engine 4 is that you can iterate really fast. We’ve already made three builds today, this morning [while showing the game at EGX], based on some bugs we ran into, and I’ll probably do a new build tonight.”
Inspired in part by Portal 2, the team is stuffing the game with puzzles in which you make use of both characters simultaneously. One mechanic allows fox sidekick Oscar to dig under obstacles like gates, disappearing beneath the earth for a few seconds.
“Before he could just dig on the spot in this one hole,” Thomas says. “But we thought that was boring, so we had the idea that you could dig a hole somewhere, using connected tunnels to teleport from one spot to the other. We decided that would make it fun to control.”
It’s certainly an evocative idea – helped by an animation flourish that sees Oscar’s position marked by the dirt above his head. But it’s also an illusion.
“With programming it’s all about smoke and mirrors,” Thomas says. “The player would probably think that we make Oscar go underground, but actually we play an animation that makes it look like he’s going underground but then makes him invisible and removes his collision on certain meshes.”
The result is a cartoon success – much of what goes on in Billie Bust Up isn’t realistic, or even happening the way it appears to on-screen. But it feels right, and that’s what made triumphs of the 3D platformers before it.
Billie Bust Up is on Patreon. Unreal Engine 4 development is now free.
In this sponsored series, we’re looking at how game developers are taking advantage of Unreal Engine 4 to create a new generation of PC games. With thanks to Epic Games and the Billie Bust Up team.