Some question the ability of new entrants to reach a wide enough fan base. Green Man Gaming, the British online retailer, sells digital keys to games that customers can redeem on a number of platforms, including Steam and Origin. The game is then added to a user’s account. Green Man takes about a 30 percent cut on each sale, while Steam makes money on in-game purchases. But the London-based company’s CEO, Paul Sulyok, said the benefits of selling through a large international retailer are worth the cost.