The game, called Play to Cure: Genes in Space, sees players pilot a spaceship through an intergalactic assault course, getting points for zapping asteroids.
While gameplay is in progress the programme is simultaneously analysing data collected by cancer scientists.
Researchers have built up a huge database of genetic data taken from tumours, and face the task of trawling through enormous amounts of DNA looking for evidence of the genetic faults that may be responsible for causing cancers.
Some of the data can only be analysed by the human eye, and looking for changes in the genome can take thousands of hours of work.
Cancer Research UK first hit upon the idea of harnessing the spare time of gamers around the world in 2012. The charity came up with a game called Cell Slider after teaming up the Citizen Science Alliance.
More than 200,000 people classified more than 2 million cancer images by playing the game and pooling their results, cutting the analysis time from 18 months to three months.
A brainstorming weekend last year saw teams of hackers, scientists and gamers come up with 12 more prototype games designed to get the public involved in crowdsourcing cures for cancer.
Hannah Keartland from Cancer Research UK said: “Every single second gamers spend playing our Smartphone game directly helps our work to beat cancer sooner.
“Our scientists’ research produces colossal amounts of data, some of which can only be analysed by the human eye – a process which can take years.
“We urge people to give two minutes of their time wherever and whenever they can – whether they’re on their daily commute or in the hairdressers having a blow dry. Together, our free moments will help bring forward the day when all cancers are cured.”