It’s a common phenomenon among rock stars: guitar face. You’ve seen it, whether it’s the overjoyed look of surprise of Eddie Van Halen, the deviant pout of Keith Richards, or the facial contortions of Carlos Santana. They are overwhelmed by their guitar supremacy, so much so that they’ve lost control of the muscles in their faces. Rock ‘n’ roll will do that to you.

It used to be that only the most dedicated shredders got to get onstage and rock out. We had to leave it to the pros, the ones who put in their time practicing scales in their bedrooms until their fingers bled. That is, until a little video game brought some of the magnificent glory of guitar rocking to the less musically talented masses.

I’m talking, of course, about “Guitar Hero,” the guitar-simulator game produced by Activision, and available for Playstation 2 and 3, Xbox 360 and Nintendo Wii. Last January, Activision announced that total sales from all four “Guitar Hero” games (“Guitar Hero Encore: Rocks the 80s” and “Guitar Hero III: Legends of Rock” being the two most recent) has exceeded $1 billion, so it might be an understatement to say that it’s a popular game.

The teens and twentysomethings gathered for a “Guitar Hero” tournament at the Center Theatre in Dover-Foxcroft last week certainly know exactly what the draw for it is: You can pretend that you can play guitar like Jimi Hendrix. Or Jimmy Page. Or Tommy Iommi. Sure, you’re wielding a miniature plastic guitar, and it doesn’t require any actual musical talent. But when you’re playing along to Metallica or Led Zeppelin on the expert level, you can feel the rock power flowing through you like a golden river of awesomeness.

“Oh, man, I was so bad at first. But I’ve stepped it up big time. I can play on expert now,” said Wayne Armstrong, a 21-year-old from Dover-Foxcroft who put on his best guitar face while playing Living Color’s “Cult of Personality.” That song was chosen by theater staff as the control song for every gamer to play during the first round of the tournament. “I mean, I can play guitar, which helps me rhythmwise, but it doesn’t actually make any difference. It’s just fun.”

The tournament drew more than 40 participants and spectators. Armstrong was neck-and-neck (no pun intended) with 16-year-old Zach Fowler, a sophomore at Central High School, throughout all three rounds of the tournament. Armstrong eventually was named the victor because of his combination of onstage antics and technical prowess. His prize? A video game party at the theater for him and his friends.

Fowler, also an incredibly proficient guitar hero, managed to perform without even looking at the screen.

“I just started playing a few months ago, but I caught up quickly,” said Fowler. “I’ve learned about a lot of new bands from it. I really love ‘Cliffs of Dover’ by Eric Johnson, and now I really like Iron Maiden. I never really knew them before.”

It’s a testament to the game’s appeal that a song such as power metal band Dragonforce’s “Through the Fire and Flames,” which you unlock after successfully beating all the other songs on the hard level, caused that band’s CD sales to jump by 126 percent. The game has been spoofed on “South Park” and on the Cartoon Network show “Metalocalypse.” Many bars and lounges, as an alternative to karaoke and trivia nights, now offer “Guitar Hero” nights. It’s an official pop cultural phenomenon.

Ten-year-old Torin Smith was turned into an Iron Maiden fan, thanks to “Guitar Hero.” Who ever said video games didn’t do something good for kids?

“I like Slayer’s ‘Raining Blood,'” said Smith, a fifth-grader at Dexter Primary School. “It’s my favorite video game. I like to jump on my trampoline and work with my Dad when I’m not playing it. I want to try playing guitar sometime.”

It’s not just guys who like it, either. Samara Hooper, a sophomore at Foxcroft Academy, came to the tournament with her boyfriend, Ryan Stroud, also a sophomore. She was the only girl to compete, and had to be coerced by Stroud to play – though it’s certainly not because she’s not a guitar hero.

“I’m a sore loser,” she said, laughing. “We play together a lot, with all the boys, and I win a lot. I like ‘Barracuda’ by Heart. It’s a really good way for everyone to hang out.”

“It’s definitely something fun for young people to do. It’s a good way to blow off steam. And I heard there were some ‘Guitar Hero’ gods out there,” said Center Theatre executive director Patrick Myers, who organized the event. “I had no idea there would be so many of them. I can barely play on medium [level]. It’s hard!”

Armstrong plays not only “Guitar Hero” but also its companion game. “Rock Band,” which incorporates drums, bass, keyboard and vocals. But “Guitar Hero” is the original, and it’s one of those games Armstrong hopes to work on when he finishes school. He’s currently taking online college classes in game software development, with dreams of working in the video game industry.

“Nowadays, a top-selling video game does better than a movie,” said Armstrong. “My kids play ‘Guitar Hero.’ You should see my 3-year-old with the guitar. It’s something you can do with the whole family.”

The mechanics of “Guitar Hero”

“Guitar Hero” works like this: You have a game controller shaped like a guitar, fitted with five colored keys instead of a fret board, and a little paddle that you flip back and forth instead of a pick.

You choose a level of difficulty (easy, medium, hard or expert), a character to represent you on screen (anything from a muscle-bound metalhead to a hot blond babe), and a song. You also decide if you want to play by yourself or on two-player. You can choose either “career mode,” in which you “tour” at different venues with your “band,” or on “quick mode” for simply playing songs for fun.

Your song starts, and a scrolling fret board appears on the screen, with colored buttons flying past (much like in “Dance Dance Revolution”) corresponding to the colored keys on the controller. In order to play along you must hit the correctly colored key as the corresponding button scrolls past on screen. Hit multiple notes correctly in a row, and your rock meter goes up. Hit a special segment of notes, and you’ll achieve “star power,” in which you can rack up extra points. If your rock meter goes too low, you lose, with the fake audience onscreen booing you.

Interesting tidbit: The highest score ever achieved on “Guitar Hero” was by a guy named Chris Chike, who scored 975,412 points on Dragonforce’s “Through the Fire and Flames,” which is generally accepted by players worldwide as the holy grail of guitar hero supremacy.