While many on the left have pushed for greater restrictions on firearm use, others have pointed to concerns about the media that shooters consume. Its creators say the game was meant to be played through the role of a SWAT team member responding to an active shooter situation, in a school. My students live in fear of going to school and being murdered.
The game's release comes less than a month after the most recent mass school shooting in which 17-year-old Dimitrios Pagourtzis allegedly killed 10 people and wounded another 10 at Santa Fe High School near Houston, Texas. "Keeping our kids safe is a real issue affecting our communities and is in no way a 'game'".
Others are too, including parents of Parkland victims.
On May 23, Acid posted a "clarification" saying they had received accusations and criticism since the game was announced. The publisher, Acid, could not be reached.
The game has been roundly condemned by Twitter users, who described it as "awful", an "atrocity," and "the vilest thing ever".
The upcoming title is called "Active Shooter" - and it's due out next week.
Trump said in the wake of the Parkland shooting that violent games are "shaping young people's thoughts".
In the days following the fatal shooting at Marjory Stoneman Douglas High School in Florida, President Donald Trump suggested he believed video games were, in part, to blame and "something" needed to be done about them.
"We have incredible, heinous violence as a game, two hours a day in front of their eyes".
But in this game, players don't kill aliens or zombies. In 2011, a Half-Life 2 mod, titled School Shooter: North American Tour 2012 was announced, but the game was never released, as it was thwarted by a backlash.
The developer also posted a video preview of the game showing graphic images of police officials and civilians being targeted.
In a following tweet, Guttenberg continued, "This company should face the wrath of everyone who cares about school and public safety and it should start immediately". Now, it's not clear that this particular video game would have the same impact, but stilll, turning an ongoing national tragedy into a game just feels wrong.
For instance, Virginia Tech killer Seung-Hui Cho had no history of playing video games, violent or otherwise.
Another remarked that profiting from the game was "sick and sad and so wrong". The game is being released on Steam, "a digital distribution platform" that allows developers to share their games without having to go through a major distributor.