Take the opening credits from Mad Men, add a dash of James Bond, sprinkle with generous helpings of Canabalt and serve. The Button Affair is an excellent auto-runner steeped in style and variety, far too good to be free and yet it is (presumably due to its short length). You should most certainly go and play it, discover that you enjoy it greatly, and then give a donation to its chosen charity, Special Effect.
The look's the main thing, a sort of 70s spy movie-themed take on Another World's coloured silhouettes, but lending a narrative and justification of sorts to what auto-runners tend to leave highly abstracted makes a big difference too. It's a shame the presentation of the dialogue is on the clunky side, as it upsets the panache of the whole affair, but never mind.
It comes off a bit like a more consciously gamey and less oblique Gravity Bone in some ways, though ultimately it is of course a Canabaltlike. Only with laserbeams, death-pits, murderous prisoners and speeding trains. A Good Time. Get it from here, then lob a quid (or more) to disability charity Special Effect to show your appreciation.