VIDEO game designers Darren and Jason Falcus are celebrating 15 years in business together.

The brothers, from Stockton, began programming in 1981 but it was not until February 1988 that they came together to launch their firm, Optimus Software.

Since then, the pair have created video games that generated retail sales in excess of $500m (£308.5m).

Darren and Jason, now 34 and 33 respectively, sold Optimus to the Texas firm Iguana Entertainment Inc in 1993 and the business was moved to Middlesbrough.

Iguana was subsequently acquired by US corporation Acclaim Entertainment and the brothers managed Acclaim's Teesside studio, in Stockton, until mid-2000, when they decided to go it alone again.

Darren said: "The first 15 years have been full of highs and lows, ranging from working 100-hour weeks, through to enjoying the luxuries of international travel.

"We have had some brotherly battles along the way, but the bloodshed has been minimal."

Having returned to independent games development, the brothers' new company, Atomic Planet Entertainment (APE), has won contracts with a number of the most important companies in the industry, to develop games across all major platforms.

Since starting trading in August 2000, APE has already achieved international success in producing the Mike Tyson Heavyweight Boxing game with Codemasters for PlayStation 2 and Xbox, Aero the Acrobat with Metro3D for Gameboy Advance, and producing DinoIsland for Wap phones.