As a teacher turned inventor, David Kotkin has always been more superhero than villain.

When a cancer survivor and fellow entrepreneur struggled with an idea for a hands-free voice box, Kotkin helped him out. For a student at G. Holmes Braddock Senior High whose hereditary condition made playing video games near impossible, he invented an adaptor called the Avenger that made controllers more accessible.

But his latest invention has sent potential partners and public relations firms —not to mention aliens and Nazi zombies — running for cover.

From the living room of his Country Walk home, Kotkin, 47, is putting the final touches on the Delta Six, a lifelike gaming gun modeled after a GSG assault rifle. Used in play, the gun moves the game view with the direction of its muzzle, zooms in when a gamer peeks in the scope and recoils with the fire of each bullet. To bludgeon an enemy, a gamer sideswipes the rifle’s butt.

“It really gets your heart going,” Kotkin said.

Or your blood boiling, depending on whom you talk to.

Tech bloggers have called Kotkin’s creation “the most realistic gaming gun ever,” and there’s probably a reason for the lack of competition: Most in the retail and gaming industry want to remain as far as possible from the debate over the role video games play in America’s culture of violence.

“While everyone else is slowly backing away from the powder keg labeled ‘media controversy,’ this guy is dancing right next to it with a lit torch,” gaming website GamesBeat said last month.

For the $16 billion gaming industry, violence has long been a touchy subject. First-person shooter games like Halo and Call of Duty are annually among the bestsellers. But the games are also highly criticized by parents and politicians, and are studied by scholars — many of whom conclude that violent games make players more aggressive.

The debate is old, but often most intense and political following incidents of mass murder, like the Columbine High School attack in 1999 and most recently, the Sandy Hook Elementary massacre in Newtown, Conn. Following both tragedies, media reports focused on video games played by the shooters.

In January, President Barack Obama called on Congress to fund research “into the effects that violent video games have on young minds.”

Amid continuous scrutiny, retailers and gaming giants have been reluctant to embrace realistic gun peripherals, opting instead for fake firearms that resemble dime-store pistols more than military grade weapons. The use of real-life models in the games themselves has also been controversial.

And Kotkin says that has left a void in the market.

“Everyone’s afraid to touch making a good gaming gun. So that’s the one area I can go into where no one’s there,” he said.

Kotkin, whose success with the Avenger allowed him to retire from teaching in 2011 and pursue inventing full time, got to work nearly a year ago. He bored out an airsoft BB gun and meticulously souped-up the gun-metal black rifle to be responsive to the touch and kick just the right amount with the pull of the trigger. He used an infrared sensor to zoom in game play when a player looks in the scope. To reload, players push in the cartridge.

Kotkin’s aim was to create as realistic a gaming experience as possible, even if it meant encouraging critics. On Kickstarter, a website for crowd funding, Kotkin did almost $200,000 in pre-sales.