See related story: Final Fight: Down for the Count

Only AFTER Lou the Skin attempts to kill you does he bother to find out who you are and that you're on the same side.
Screenshot: Courtesy of Capcom
"Decent" is being far too kind.
Screenshot: Courtesy of Capcom
Killing bad guys ups your "respect meter," which has no noticeable effect on gameplay other than people in town congratulating you as you walk by.
Screenshot: Courtesy of Capcom
But wait: a glimmer of hope? Rooting though Cody's things, you find... a picture of Mayor Mike Haggar, one of the characters that made the original Final Fight so awesome.
Screenshot: Courtesy of Capcom
Speaking of which, the original Final Fight is included in this game, except it doesn't look nearly as good as this screenshot.
Screenshot: Courtesy of Capcom
Vanessa the no-nonsense bartender proves herself to be an absolutely worthless ally, getting herself killed (forcing you to restart the mission) over and over.
Screenshot: Courtesy of Capcom