Dirk Van Welden, a Belgium-based mobile and PC game developer, was in the midst of two big projects last year when he donned one of HTC’s prototype virtual reality headsets, forever changing his career. “I am like, ‘I’m going to drop every single project I am working on now,’” he said.

A year later, his old work left unfinished, he’s become one of the best-known developers in the burgeoning field of virtual reality thanks to his arcade-inspired game, “Space Pirate Trainer,” which was crowned the top game at this year’s Proto Awards (the Oscars for virtual reality). More than 60,000 people have bought the $14.99 game so they can blast flying, laser-wielding killer robots coming from every direction. Mr. Van Welden says success hasn’t made him rich. In fact, there’s no telling if any of his work in VR will pay off in the long run. “Everyone is taking a risk working in VR,” he said. “We’re not in it purely for the money.”