Perfectly charming and perfectly twee, but perfectly ingenious with it, One and One Story is a two-player game for one person.
A superficial glance will tell you that it is a lo-fi platformer of the sort which litters Kongregate and similar, while a superficial play will tell you that it has an awful lot in common with the inner-monologuing and character-switching of Thomas Was Alone. Both these things are true, but both undersell what's a tightly-executed ten minutes.
You play as a couple, separated by distance, jumps, drops and spikes, and in each level you must reunite them. Initially this just means making the apparent male perform a few simple leaps and bounds, then soon enough you must switch between each character to bring them together.
Just as that seems to be the game's course, it has one of the characters computer-controlled, marching relentlessly to their doom unless you can intercept them en route. Then each character mirrors or inverts the other's actions. Then... Well, it's a finely-tuned and ever-changing creature, and though it may be said to be too short and too easy, and its visual and written style leaves much to be desired, there's a real completeness to it. Recommended!
The music sounds rather like a more saccharine James Blackshaw to me, but of course this would have been the ideal soundtrack: