Despite its intensity and clever design, Epic Games' first foray into an entirely original virtual reality game still has no promise of a street date.

After spending an hour explaining to an audience of developers and press how Epic tackled a number of key issues found in VR game development while creating Bullet Train, the project's lead designer broke their hearts.

"You're not going to see this in the foreseeable future," Nick Donaldson told one attendee, when asked about a release date.

It remains unclear why that is, but Nick Whiting, technical director for VR and AR at Epic Games, said that the playable level of the game — the only one that exists — could be made into a full game.

"The experience does scale," Whiting said. "This is only one level. If you layer on top of that game-isms like combos, scoring, different environments, you can scale it up.

"If you've played it a few times you start getting much more physical with it, and then hygiene and fatigue are limiting factors."

The game has already grown quite a bit since development started on what was to become Bullet Train. Whiting told the audience that the game was a direct byproduct of both what Epic had done in the past and where VR game development might head.

Epic's first foray into VR was shown at E3 in 2013, a simple demo. Next, the company created a tabletop game demo. Then Epic created Couch Knights to play with the idea of multiple people using the same game space. In 2014 came a demo called Showdown, which was meant to show how cinematic a VR experience becomes when running at 90 frames per second.

Last year, the team worked with Weta Workshop to turn a moment in The Hobbit films into a purely visual VR experience.

"All of those things had something in common," Whiting said. "We adapted content we already made into VR."

For its next VR demo, Epic decided to build something from the ground up, a playable demo that uses the Oculus Rift's touch controllers, leans on the learnings from previous demos, and pushes what the team knew forward.

The goal was to create a game built for a GTX 970 graphics card — a step down from the card needed to run Showdown — but to make it look better.

The developers also wanted to make motion controls to be a central part of the game.

And they only had six weeks to flesh out the idea.

Epic eventually showed off the Bullet Train demo during last fall's Oculus Connect event. In the short demo, which we adored, players fight around a train station shortly after disembarking from a bullet train (get it?). The game uses Oculus Touch controllers to control its guns. Instead of reloading, players simply drop or throw away their guns and grab new ones. Players can also slow down time and pluck flying missiles out of the sky to redirect them at enemies.

But months before, the team's first approach for the Bullet Train prototype was a shooter that played a bit like a virtual reality version of the light gun arcade classic Hogan's Alley.

"It was a basic shooter gallery," Whiting said. "We had a table filled with weapons and bots would run at you. You could pick up the weapons and use them and blow the crap out of everyone."

Then the team thought of turning that concept into a co-op multiplayer game, with two players standing back to back, facing two alleys as they tried to take down waves of enemies.

But both approaches got boring quickly, he said.

So the developers went back and started looking at what makes shooting interesting in movies. They quickly realized that to make the game more fun, they were going to have to deal with the issue of movement in VR, a problem that's hard to address without causing motion sickness or unease in some players.

They examined Asian action films like Oldboy and Hard Boiled, and liked the idea of doing a single camera shot. The idea was to follow alongside the player as he or she worked their way through a stream of enemies with a seemingly endless combination of gunfire and physical attacks.

"The one-shot solved the motion problem because the camera is moving through the action continuously," Whiting said. "We also control the path. So we can do things like change directions and have players go through those movements. And there would be a lot of chaining. As you go through the scene, you attack one guy, punch him, shoot that guy, take his nightstick and beat the next guy with it.

"It looks like you're a badass and you feel like a badass."

The problem the team ran into was that players would start to turn and eventually obscure the tracking cameras, basically breaking the motion tracking.

Eventually, the team came up with the idea of minimizing movement by allowing players to teleport around a map. They could still move if they wanted to, but by combining the ability to teleport with some smart design decisions, the game was able to mostly keep players from walking around too much.

First, the game takes place in a train station. A train track running through the center of the game map is a natural, though subtle, reminder to players not to walk across the map, but rather to teleport.

The team also programmed enemy AI to move toward the center and make sure the boss of the level appears and stays in the middle of the map.

Once Epic layered in the ability to teleport to different sections on the maps to get weapons, take out enemies and move away from danger, players simply didn't feel the need to manually move much.

To highlight the fun of chained attacks, the developers worked in a few other interesting tricks.

Bullet Train uses a stealth teleport to essentially always move you close enough to an enemy that you're trying to punch, if they're already pretty close to you.

Unbreakable

It turns out that playtesting an in-progress game for the Oculus Rift and its Oculus Touch controllers can sometimes result in frustrating moments. During their GDC talk, the Epic duo mentioned some of the incidents that the touch controllers survived. Being thrown across the room.

Being thrown into a wall.

Being punched into a wall hard enough to remove some of the plaster. "These controllers are indestructible," Donaldson said.

Epic also tweaked the way some of the harder weapons, like rockets and grenades, work. If you keep missing with your throws, the game starts to subtly, slowly auto-adjust the trajectory of your toss to make sure you hit what you're aiming at. The assist on those throws went through a lot of iteration before Epic found the balance between helping a player to have fun, but not coddling them.

"It's really hard to fail," Whiting said. "The longer you suck, the less you suck."

The developers also made it impossible to die in the game.

"We didn't allow failure to be an option," he said. "There's no death; you only become more badass."

The end result is a game that quickly makes you feel like you're a badass, throwing weapons at enemies to stun them and then teleporting by their side to grab that same weapon as it falls and use it to kill them.

The team hammered on playtesting and continued to add new twists and ways to have fun. That included being able to juggle your weapons between two hands to quickly switch which hand is holding which gun; racking the shotgun as seen in Terminator 2; and being able to toss a grenade and then shoot it out of the air.

Bullet Train lead Donaldson said Epic even played around with the travel speed of bullets, just to make sure players caught a glimpse of them.

"Our solution was to slow the bullet down to a quarter of its original speed over one-tenth of a second and then to speed it up to 1.25 [times] the original speed over time," he said. "The total time is about the same, but early on it's slow so you can see it."

While Donaldson enthused about living through "oh shit" moments in Bullet Train, he also made sure to point out that VR gaming is still very much in its infancy.

"It's like the early mobile game days," he said. "I think it's the same with VR. You're not going to get [a VR headset] to play 120 hours of Skyrim on your couch.

"I think it is going to be a completely different sort of games that succeed."