Nintendo is still disappointed, though, as it had hoped to get a double-digit conversion rate. And if you consider how some of the dedicated mobile game makers fare, it's easy to see why there would be some disappointment. Clash of Clans developer Supercell, for instance, raked in nearly $1 billion in 2015 through three games. While Super Mario Run is just one game, it has the advantage of an extremely recognizable brand name and a higher-than-usual in-app purchase price. It'd ideally be a cash cow all by itself, even though it only launched on iOS at first.

You could see a change of fortunes soon. Super Mario Run will reach Android in March, and big-name franchises like Animal Crossing and Fire Emblem are also on the way. Smartphone gaming may well become a major source of income for Nintendo -- it may just take a while to get there.