Teen with heart disease imagines video game now sold in app store

— -- Hunter Allis is only 14 years old, but he has already helped to create his own video game available in the Apple App Store.

Hunter, of East Hampton, Conn., was born with hypoplastic left heart syndrome, a rare congenital heart disease. He had three open heart surgeries before he was 3 years old and a fourth heart surgery at age 11.

Unable to do much physical activity, Hunter developed a love for video games. He would fill notebooks with sketches of video game characters.

"I just like creating things," he told ABC News. "And I just really like video games."

Hunter was recovering from his fourth heart surgery in 2014 when he learned he would have a wish granted by the Make-A-Wish Foundation. He immediately said that he wanted to create his own video game.

In May 2015, Hunter and his family flew to Texas to spend five days at Bottle Rocket, a Dallas-based company that creates mobile apps.

Hunter, then 11, signed a "contract" to join the team as the head of their gaming division for the week. He brought his sketches and participated as the developers at Bottle Rocket brought his video game idea to life.

"Looking back on our time with Hunter, it is still one of our proudest moments as an organization," Bottle Rocket founder and CEO Calvin Carter said in a statement. "The fact that we were able to leverage our craft and passion to help make his wish a reality means the world to us."

Hunter named his game "Planet SRAM," which is Mars spelled backwards.

"It was really neat," he said about the process. "I remember I was just drawing stuff on the board and they would try to put it in the game."

Hunter left Bottle Rocket at the end of the week with the game installed on his father’s iPad. The game stayed there, available only to Hunter and his family, until earlier this month when it was released to the public.

"I was actually stunned," Hunter said. "I didn’t think they were going to put it in because it had been a couple of years."

The game is free and features a message from Hunter: "My wish was truly a 'game-changer' for me. I hope you enjoy Planet SRAM as much as I do."

Carter described working with Hunter was "one of the most powerful [experiences] in our company’s history."

"The experience changed us as an organization and allowed us to draw on our passion and unique skills to bring joy and satisfaction to a very deserving and imaginative young man," the Bottle Rocket founder said in a statement. "We are proud that the rest of the world can now hear this story and experience Hunter’s wish for themselves.”

Hunter’s mom, Erin Allis, said creating the video game gave Hunter a sense of confidence and helped to confirm his career path.

"He’s now attending a magnet school and is very determined he’s going to make video games," she said. "It has given him a goal so he’s not as focused on his health."

"When your child is sick, you have bad memories," Allis continued. "So the time we spent at Bottle Rocket as a family and to see Hunter so happy after he’s been through so much was amazing."