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Runaway director Tim Nixon said the gaming studio - which is a division of NHNZ - was carving out a successful niche publishing free-to-play games based on natural environments.
After having more than two million people download its Flutter: Butterfly Sanctuary on Android and iOS, it released Splash: Underwater Sanctuary on Friday, Mr Nixon said.
Early feedback had been positive and 10 new positions were being advertised for the division, which now had 14 staff, 12 based in Dunedin.
''We have doubled the team size in the last year and our ambition is to do the same over the next year as well.
''The success of Flutter gave us the flexibility to reinvest in expanding that portfolio.''
The amount of expansion would also likely result in the company having to move out of the NHNZ offices and to another Dunedin location.
''We don't know exactly when, but it's absolutely on the cards.''
Much like Flutter: Butterfly Sanctuary, the new game was based on the model of raising and collecting animals, but this time it was sea creatures instead of butterflies.
''We have definitely taken everything we have learnt from Flutter over the last two years and used all that learning to refine some of the fundamental game play mechanics.''
A key change was that instead of keeping their animals, users would now release their sea creatures into the wild once they were fully grown, helping to repopulate the virtual world in which the game was set.
This was the ''riskiest'' change, but he felt it ould help keep the game fresh.
Since Friday, 150,000 people had downloaded the app and it was already equal to Flutter when it came to how many people played it each day - about 70,000.
He was most proud of the positive reaction from the new game's users, most of whom had come across from Flutter.
The plan was to release two more games, based on the same formula but set in different natural environments, next year.
The company made money from the games by giving away the app for free, but offering people the option of paying to speed up the game's progress or for premium content.
However, Mr Nixon was keen to make sure the company's games could be played through without people paying.
Its biggest market was 18- to 35-year-old North American females, but Flutter was popular across all age groups.
Many parents played it with their children.
NHNZ managing director Kyle Murdoch said what Runaway had done was ''incredible''.
The division's success fitted perfectly with NHNZ's vision to be a content production company, rather than just a TV production company, he said.