Tandem Capital had a humble start in a home in Burlingame five years ago. But now the incubator (which calls itself an accelerator) has raised $32 million and it has begun to specialize in investments in mobile game startups and mobile platform technologies.

The company makes investments in small groups of companies, usually about $200,000 in six companies every six months or so, said Doug Renert, co-founder and chief executive, in an interview with GamesBeat. Tandem isn’t all that interested in hit-driven mobile game studio investments. But it is always looking for mobile game platforms and technologies that could give those studios an edge.

The formula has worked so far for Renert and co-founder Sunil Bhargava. The company made investments in 10 startups in its first round, and nine were successful either through growth, new fundings, or acquisitions.

“We’re off to a great start with our second fund and we have narrowed our focus to mobile during the past year,” Renert said. “We keep our fund small and our investments small because lean startups don’t need as much money. We make very few investments and are the opposite of ‘spray and pray.'”

“It’s harder for the later-stage venture capital investors to get into deals like this,” Renert added. “It is worrisome as an investor to see so many game studios being backed. Very few of them will succeed and give investors a return on capital. But we do like investing in platforms, like selling blue jeans or shovels during the Gold Rush.”

In gaming, Tandem invested in HTML5 mobile monetization firm PlayHaven and BitRhymes, producer of the popular Bingo Bash social casino game on the iPad. PlayHaven’s platform is servicing nearly a billion monthly game sessions with HTML5 pop-ups that increase engagement in a game. BitRhymes recently said that it is on a $45 million revenue run rate. Outside of games, Tandem has backed Juice in The City and Zumodrive. Its latest investments include A-Blast, Appington (an audio platform for mobile game developers), Heyyolo, Nusonix, Parkify, and QuadNode.

During the past year, mobile game investments have skyrocketed, accounting for a third of all game investments, according to Digi-Capital. While game acquisitions have soared in value, the number of game fundings is slowing down and the amount raised per money is smaller. Renert said he isn’t surprised at that data, given that it takes a small amount of money for app makers to bring a game to market and become profitable.

“I am bullish on gaming because we are not doing that many game investments,” he said. “If I were doing 10 or 20 deals in games, that would be hard.”

It competes with other incubators, like Y Combinator or YouWeb, which is down the street. But more often than not, it partners with YouWeb, and it makes larger investments than many incubators do. Once it invests, it supports the startups for six months, working actively with entrepreneurs in technology, strategy, and hiring.

“YouWeb likes to back entrepreneurs and work with them on ideas. We want to back great teams that are off and running and focused on a big market,” Renert said. “We call this muscle capital. We want them to use it to build a big business.”

For the future, Renert said he is interested in “second screen” investments where you use a mobile device in conjunction with watching TV on a big screen. Social sports betting has potential as does elevating the effectiveness of mobile advertising, he said.