You do not kill John Wick's dog. You will not be happy with the results.
Here's the trailer for John Wick, playing Fantastic Fest this year, and a very ass-kicking cinematic action experience. Keanu is John Wick, a hitman who has gotten out of the game until the son of a mob boss kills his dog and steals his car. What follows is a fucking orgy of violence set in a semi-stylized underworld of mobsters, killers, fixers and molls. It's the kind of movie where the world's assassins all stay at the same hotel and drink in the same bar, where the rules are that no business can be transacted on the grounds. It's also got a ton of great actors throughout - Willem Dafoe, Ian McShane, Lance Reddick, Adrienne Palicki.