The music is the gameplay

How to make an interactive rock concert as epic as possible.

As soon as we started work on bringing Metallica to Fortnite, we knew we wanted to push the boundaries of both interactivity and visual immersion. We wanted to take inspiration from previous Fortnite concerts like the visually explosive Travis Scott’s Astronomical and the deeply interactive The Kid LAROI’s Wild Dreams, and combine them to create insane visuals with satisfying interactivity.

Fast-forward a few months and we’d realize that we’d have to get seriously creative to fuse spectacle and gameplay into a seamless, musical experience. Here's what we learned in the process…

Get the full playthrough of the Metallica x Fortnite event in this rock-powered video .

Cognitive load & simplicity

The players’ ability to ingest and respond to what they’re seeing is a critical factor in any interactive experience; however, when that experience is synced to music, everything happens to the beat, and players are swept along with the tune, rather than having control of what happens when. We took a few crucial steps early on to help prevent overstimulation for players.

First off, we set out a clear structure where sections of the experience would alternate between heavy interaction and a visual celebration of the band.

The “Stadium” sections were designed to recreate the feeling of being at Metallica’s world-famous live shows, providing players an opportunity to get right up next to the band and appreciate the painstakingly mocapped performance.

The first stadium section - where players could rock out to Hit The Lights.

Each segment was book-ended with a brief cut-scene to provide a narrative through-line so any changes in activity or location made sense. In retrospect, these probably could have been longer, as they were critical to the flow – something to bear in mind when designing the structure of your experience.

For our interactive sections, we made sure that the core gameplay would be familiar to Fortnite Battle Royale players – driving, jumping, shooting and so forth. 

During these segments, all key visual elements were placed directly in the players’ sight line, so they never had to miss the show while playing.

Band members warp in on the outside of a circular path, keeping them in the players’ sight-line.

And finally, we employed reductive design to focus on the essence of each section, to keep things as simple as possible.

The problem with creating simplicity is that it’s harder than you might think. Less content requires less design, right? Unfortunately, the usual path to a beautifully simple design is to make something really complicated, then slowly chip away the noise until the core experience shines through. 

For example, one of our high-level objectives for this experience was to recreate the physical chaos of the mosh pit using familiar Fortnite mechanics. We spent a lot of time experimenting with bumpers, flippers, d-launchers, impulse grenades, bounce pads, and more, each deployed in myriad combinations. We found a number of executions that really nailed the vibe and fun of the mosh pit, but somehow they took the user out of the concert experience. In the end a simple up-and-down bounce was all we needed.

Difficulty & pacing

It’s worth noting that the simplicity of a game is not necessarily linked to its difficulty.  Even a concept as elegantly simple as Tetris can be challenging for the player when the appropriate parameters are switched up. We needed to make sure that players of all skill levels could enjoy the experience on their first playthrough, and never fall out of step with the musical flow. 

We also wanted to change the gameplay with each new song. We had five songs to fit into a 10-minute experience, so we limited each song to around two minutes, which didn’t allow a lot of time for gameplay mechanics to develop.

In any interactive experience, players need to instantly understand what they have to do, so we deployed short, in-world text at the start of each section to make any objectives extremely clear: “Grind the lightning!” “Ascend the clock tower!” “Get to the show!”. These simple instructions were tricky to get right because the less words you have, the more each of them matters. When possible, we made sure these objectives had a visual component in the level to make sure players knew exactly where to go.

Players need clear objectives, both written and visual, to provide context, motivation and direction.

To correctly pace the levels we had to break our core mechanics down into tunable metrics (the numerical parameters of gameplay).

For example, if players have a gap to jump, there are parameters you can tune like the width of the gap, the relative height of the landing or the size of the landing area, all of which will affect how difficult it is for players to successfully traverse that gap. Using these parameters it’s possible to define what easy, medium, and hard versions of your gameplay elements look like. 

We made sure that the first time a player encountered a mechanic, it was the easiest possible variant, and the section contained that singular mechanic only, reducing the cognitive load and creating a gentle onboarding for each element. This was most evident in “For Whom The Bell Tolls” where we introduced players to rhythmic steps, swinging bells, and rotating cogs each in their own, isolated sections, before bringing all those elements together for the most intense part of the song.

This parametric approach can also be used to map the gameplay to the music. For each track, we mapped out the various segments of gameplay directly over the top of the music’s waveform, making sure they matched in both intensity and theme.

The initial gameplay map for For Whom The Bell Tolls.

We also went to great pains to make sure that no matter a player’s skill, nobody got left behind. Different techniques were deployed for each section – in the race section for “Lux Æterna” we tuned down the boost on the cars so the difference in speed was mostly perceptual (shhh… don’t tell anyone!) For other sections, we created a dynamic respawn system that would revive fallen players at the optimum location relative to the music (this was less effort to implement than it sounds – a single respawn point, animated to move through the level in between beats – easy). We also broke larger sections of gameplay into smaller segments with their own discreet objectives; faster players would reach these first and chill with the visuals, or dance with the band, while slower players would have a chance to catch up, before everyone warped onto the next area together. 

Musical immersion

Perhaps most importantly, it was critical for us that Metallica’s music didn’t feel like a tacked-on soundtrack: players had to feel like they were playing the music. With this in mind, we embraced something we call Ludo-rhythmic Resonance, which has three key pillars: visual, spatial, and mechanical.

Visual is the whole game world pulsing to the beat. Do anything and everything you can to make the environment pump in time with the music. Assign different visual elements to different instruments: shake the screen on a crash cymbal, pump the FOV on the kick drum, explode lava when the vocals kick in, desaturate as you build up to a drop then pop the color back in when it hits. This way you’ll create a visual language for the sound that players will subconsciously translate, immersing them in the music.

The volcanic racetrack of “Lux Æterna” has eight unique visual components, each mapped to various musical elements of the track.

The spatial element is all about the metrics of rhythm. Knowing your metrics is the keystone of quality level design, so we spent a good chunk of our pre-production building test levels, or ‘gyms’, where we could reverse engineer Fortnite’s metrics, and map them to the music. For example, in the jumping sections of “For Whom The Bell Tolls”, the platforms are spaced so that players can run and jump in time with the music. In our racing section, assuming you are going full speed, the curves switch direction every four bars creating a rhythmic slalom. Stimulating a rhythmic input is another key tool for reinforcing that musical immersion.

And finally, the mechanical element refers to synchronizing as much gameplay as possible to the beat. The volcanic jets in our race track all fire in time with the power cords, the boss always attacks every eight bars, machine guns have a rate of fire that matches the track’s BPM, the bells in the level swing when the bells in the music swing. As luck would have it, in “Lux Æterna” the cars’ turbo was already tuned to the right tempo, which meant you could double-tap it to the beat for extra boost. And the more juice you can layer onto your mechanics, the more players will feel the beat. Once again, this all gets the player thinking and playing rhythmically to completely immerse them in the sound of Metallica’s music.

The Master of Puppets shoots his death rays in time with the music, while machine guns rattle to the beat.

Put it all together

The end result of these elements creates a seamless experience full of intense gameplay, where players always know what they are doing, never get split up, play in time to the beat, and get fully immersed in the music, while still having the chance to chill and just rock out with the band.

In the “Enter Sandman” finale lights, fire, lava, lightning, speakers, camera, and d-launchers all fire to the beat!

Along the way, we had a lot of help and support from the good folks at Epic, most of whom had worked on concerts before and/or were Harmonix alumni, so big thanks to them for sharing their extensive expertise and experience!

Hopefully, you got a chance to play Metallica - Fuel. Fire. Fury. (or at least watch a streamer play it) and experienced these design principles in action. We hope you'll agree that they make for a truly epic rock experience!