For whatever reason, there seems to be a lot of crossover between die-hard gamers and headbangers.
When we're swapping favorite bands, not many mention the particular branch of metal that I grew up on (Pantera, C.O.C., Anthrax, Alice in Chains, Metallica, Ozzy, etc.). But there's a ton of gamers of the FPS, sports and MMO crowds who cheer to one brand or another of rough, nasty guitar and pounding drums.
And every headbanger knows how some good metal can really get the adrenaline pumping. There's a reason the U.S. Armed Forces usually use metal in their recruitment ads on TV. My brother and I used to joke that, "This song makes me want to kill somebody!" My cousin once described a scene of a battlefield while we were listening to "Bury Me in Smoke" by Down, and to this day that image comes to mind whenever I listen to it.
Anyway, so I started wondering how metal might be better integrated into a video game, and this is what I came up with. Sounds and music are hard to describe, but I'll do my best.
Swing to the music
How about a fighting or action game that rewards moves being in time with the music?
Some songs would make this relatively easy. If it's got a pretty steady beat, the player just has to land one of a set of moves on the beat.
Other songs, like "Vote with a Bullet" by Corrosion of Conformity, would have more variance and expect more of the player. These are songs with crescendos (build-ups) and rhythmic tricks. If there are two "taps" before a "punch" in the music's rhythm (like a triplet with the last note accented, for you musicians), then the player is rewarded for executing a spinning move which lasts roughly the duration of the three notes. If one note is emphasized more strongly than another, like when the drummer comes down hard on the crash cymbals, then a stronger attack is rewarded.
Mosh to victory
If it was a fighting game, ala Street Fighter or Tekken, then I would make the game about simple moshpits.
For those who aren't aware, a moshpit is an area, sometimes lowered (a "pit"), at metal concerts where headbangers start dancing violently... pushing, ramming, and often elbowing each other. In this game, the violence would be exagerrated... beyond believeability, to ensure nobody can reasonably think the game is encouraging such behavior in real life. Honestly, most headbangers hate people who throw punches in a moshpit.
It could be point-based, but I think a "last man standing" mode would be more fun. Imagine being in close-quartered fisticuffs with 15-20 other guys. The music's blaring. The crowd all around you is cheering and it pushes wanderers back into the fight if they get too close to the edge. As participants in the moshpit get knocked out, there's more and more room in the pit. The increased space allows for greater maneuvering, but it also opens up the possibility of moves/skills which require a certain amoung of room. If the first song ends, then you all get a breather to strategize and regain some energy before the next song starts. When the fight is over, the crowd roars with delight and the victor gets picked up to crowd-surf onto the stage with the band.
There might also be an endurance mode, in which you last as long as you can in the pit while more contenders trickle in from the surrounding crowd. You can then compare your time and points (for spetacular moves, combos, and maybe difficulty of dynamically added mosher types) to other players online.
And you could compete directly with 2-4 of your friends locally (if the game offers a wide and somewhat top-down view) or with more players online. Earn mulitplayer titles, new character customizations (a mohawk, piercings, tattoos, etc.) and other rewards. Earn emblems of your favorite bands to tattoo on your character or wear as badges on your jacket.
Really, the above sounds like the better integration of metal, but it might also be tied into an adventure game.
I'd probably make the setting a gritty, urban environment with street battles. The weapons would be either melee stuff like bats, crowbars, brass knuckles and the like, or guns. I'd love to hack-and-slash with weapons to the rhythms and movements of the music. Movements in the music might even open up skills and opportunities not otherwise available.
For example, the beginning of the solo of Ozzy's "No More Tears" might take the game into slow-motion, with fire erupting in a ring around the player (possibly just a visual, but scorching the enemies surrounding the player if he's lucky) when the crescendo reaches its climax and the solo really gets going.
For this sort of gameplay, it wouldn't have to be restricted to metal or even popular music. I could make a pretty cool dungeon crawl experience out of Grieg's "In the Hall of the Mountain King" or other classical tunes.
Honestly, I'm not sure how I'd work this into a full game, but I think it might be possible. But I'd love to take all of my favorite songs and work them into adventures and events like that. It would probably have to be some other sort of adventure game, perhaps one that's largely on rails, like Bioshock.