Harmonix's new game is a musical shooter. Seriously.

This is only a summary of my interview with Harmonix's John Drake and Nick Chester about upcoming game Chroma. For a full 6,000+ word transcript of my interview, go here.
Harmonix struck plastic-instrument gold first with the Guitar Hero series and later with the Rock Band series. Then the company made some of the only titles worth playing on Microsoft's Kinect, with it's finely-tuned Dance Central franchise.
So where does the rhythm company go from there, now that all those plastic instruments are ending up in plastic-instrument graveyards?
Two words: Musical. Shooter.
Seriously.

Chroma is Harmonix's new musical first-person shooter.

March to the beat of the gun

"This is the best demo we've ever done. There's no gameplay. There's a sixty-second teaser trailer. And then us yelling at you," says Harmonix's own John Drake. We're sitting in his hotel room during D.I.C.E. as he and fellow Harmonix-ian Nick Chester attempt to explain the studio's latest experiment—an experiment so crazy, the company is releasing it free-to-play so nobody has an excuse not to play it.
And yeah, it's a first-person shooter based around music, titled Chroma. "The hope is that music is meaningful to every moment of gameplay," says Drake, laying out the game's ambitions. Chroma is being developed in conjunction with Hidden Path, the studio responsible for Counterstrike: Global Offensive.
Let's say you have two teams—one that's themed around Rock music, and one that's themed around Electronica—and they're battling for control of points on the map. If you control a point, that area is bathed in the soothing tones of your own team's base music. Enemy territories are occupied by the opposing song.

So pretty.

Music factors into the game in three different tiers: generative, beat-matching, and meta.
Generative is easy: "Weapons you fire are creating sounds," says Drake. Which, he's quick to point out, is a silly way to put it, because weapons in a game always make sounds.
But these weapons make musical sounds. The gun basically draws on a library of samples, which it plays back in time with the underlying music of the match. Instead of bullets, you fire waveforms in the shape of whichever sample is playing.
"You're shooting light weapons out of the end of your gun and you're detonating grenades off a beat and everything feels like it's this crazy concert experience," says Drake.

"Everything feels like it's this crazy concert experience."

The beat-matching aspect is more in the vein of traditional rhythm games, but you may choose whether to play along.
It's subtle. Press the Spacebar on the downbeat, and you might jump a little higher. Hit Shift on the downbeat, and you'll dash a little faster. You can still dash or jump at any time, but doing it in time with the music nets you a small boost.
There are also classes with a heavier rhythm game influence, like the Engineer. The Engineer's gun has a track—imagine Rock Band's note highway—coming out of the front. You have to press the left and right mouse buttons in time with the note stream in order to make your gun fire.
To make up for the fact that paying attention to the beat-matching is hard during a shootout, the gun locks onto enemies until they duck behind cover.

You only have to beat-match if you want to.

"We ratchet down the shooter difficulty a little on that class, but we ratchet up the beat-match difficulty. So it's like, hey, if you're a music player and you know you can own beat-match, maybe the Engineer class is great for you," says Drake.
There's a pistol that does more damage each time you successively fire the weapon on the quarter note of the underlying match music. Fire the sniper rifle on the downbeat and it's an automatic one-hit kill, but your target might be gone before you get the opportunity to fire on the downbeat. There's a fast-travel system that you can enter only if you jump in on the downbeat.
Small, but important, tweaks to the shooter formula.
And finally there's the meta-level. Think about the point in a song where the verse leaps triumphantly into the chorus, or slows down to go into the bridge section. Harmonix has channeled these moments into the physical design of Chroma.

Chroma concept art.

"We give you a little four-bar preview where we draw in some geometry in wireframe and at that moment, the geometry will grow out of the world and the beacon you were trying to capture is suddenly forty feet in the air and have a bunch of fortifications around it, or a sniper tower will spawn in the corner of the map," says Drake.
Drake admits it's disorienting the first time you play a map, but he likens it to knowing meta-level tactics in other shooters (where people spawn, where guns are located).

Not just Rock Band with guns

"When I say musical shooter people think [of beat-matching]—'Oh, do I just shoot to the beat and that's just what you do?' Well, sort of, but other classes not at all and in certain ways you don't have to do any of that," says Drake.
For example, when members of Harmonix play against members of Hidden Path, you can really see the two different sides of the game. Harmonix approaches Chroma like a rhythm game, using classes like the Engineer and really engaging with the beat-matching. Hidden Path plays it like a shooter.
Neither is wrong.

Like a cyber-y ballet.

"Eight people shooting a musical weapon of one kind, eight people shooting a weapon of another kind. All these light beams, rockets and grenades shooting across the field in music and detonating in time and people jumping in time and zooming across the map and these beat-match traversal pads," says Drake. "It starts to look from a spectator perspective like a crazy gun ballet in a near-future world that's a little cyber-y."
Harmonix is releasing a closed alpha at the end of February. To sign up, test, and help develop this crazy game of theirs, you can go here. Fair warning: This is a true alpha, with only four months of development under the team's belt so far. The experience is rough, the art is rougher ("Like a polished PS2 game," says Drake). If you're looking for a different kind of shooter, though—well, Chroma is certainly that.
Again, I wrote up my 6,000+ word transcript of my interview with Harmonix's John Drake and Nick Chester and posted it over here. If you're looking for more information about Chroma, that's a great place to start.