With a fair 'one person buys' setup
The other day I ran across a newly released shooter for iOS and Android called Dual. The whole gimmick is that it uses two devices to function, with a screen that spans between them. By forming a tenuous Voltron-esque link you can play two modes, versus and co-op.
Although it is a free download, thankfully, only one person needs to buy the premium version ($1.99) to play the latter mode.