Kaiparasoft writes games under the Ninja Kiwi name and gets 70 per cent of its revenue from users of Apple iOS and Android devices. That proportion is set to increase thanks to its latest release, a game called Bloons Tower Defence 5, which went straight to No2 in the iTunes App Store in the US, with help from the mobile development expertise of Digital Goldfish.
"Our strategic plan in buying the Scottish studio was to do a lot more mobile development," Harris says. Not that Harris - the former financial adviser - imagined the business would expand so quickly. He was roped into it by Stephen, who abandoned a geophysics career to get a qualification as a games designer.
"I was quite interested in developing a business that would make a passive income," says Chris Harris. "Things turned out even better than our naive expectations - it was only about six months before we began doing it full-time.
"Many people have quite accurately described the internet in general and mobile game development in particular as something of a goldrush."
Some prospectors perish without hitting paydirt and others find a fortune, he says. "There are a number of factors that play into the success formula, but you certainly can't predict it."
That's not say it's all been smooth sailing. For all the success of the new Bloons, which costs US$2.99 (NZ$3.60) but was discounted to US99c for Christmas and by mid-December had been downloaded 330,000 times, other games have cost the company tens of thousands of dollars but have failed to fly.
The trick is to create one in which users are happy to invest their time - and a little money, Harris says. "When you consider that going to the movies costs $15, that's the equivalent of 15 99c iPhone games, which will give you countless hours of play."
He doesn't see the goldrush ending soon, as the internet, social media and mobile markets continue to develop at a fast pace. But he is not prepared to risk the company culture by accepting an investment from a venture capitalist to accelerate Kaiparasoft's growth.
"We're self-funded and we'll continue to be. That's not to say that at some point in the future someone won't decide to make us an offer for the whole business that is too good to refuse.
"But we're just having too much fun at the moment - it's really cool being in control of your own destiny."