In 1987, Gultnieks was hired by Vektor Grafix, a British computer game company. He was the first employee, along with two founders. The three men were tasked to port Star Wars: The Arcade Game to home computers. After the success of that project, Vektor Grafix was tasked to port The Empire Strikes Back in 1988. Gultnieks worked on more games with the company, until it was bought out by MicroProse in 1992.
He stayed with MicroProse through the release of the flight simulator Dogfight. In 1993, MicroProse was bought out and closed down their UK office. Gultnieks set up The Software Refinery with Ian Martin and a few other programmers. That company released Slipstream 5000 and Hardwar in the 1990s, and closed down in 2002.
Hardwar, the last video game Gultnieks created.