Well, the thing to remember is that ***SPOILER ALERT*** we're being lied to the whole darn time, so every clue deliberately points to the wrong guy. We don't get a good look at the bulletin board until the end (though you can briefly glimpse bits of it earlier). The shot of the pile of rope cross-fades to the real Keyser, to leave the vague impression that you saw him behind it when you really didn't. And so on. Listen to the commentaries and you'll find out what the filmmakers did to misdirect you without cheating outright.
Heh. Yeah, nice touch. Of course, it was theoretically possible that "the cripple" did that out of some sort of necessity; easier to light? Easier to pick up or put down? But yeah, you spotted one of the very few clues that wasn't a lie or distraction. And, of course, getting his interrogator to pick up the lighter was not only a stalling tactic but a long con trick; it's how they can test for a good mark...
well it was about 15 years ago i saw the film so i might get a few of the details a little wrong, but, Kobayashi seemed more suited to be the master criminal, why would someone as powerful as Keyser go on a risky job when he could watch from the side lines?
Many people who watch psychological thrillers/neo-noire movies expect a twist ending. This in itself tips off viewers. Also, some might be able to match Keyser's voice in the beginning to the actor's voice, since he was really just whispering. Personally, I saw a documentary that gave away the ending before watching the movie, so I can't be sure if I would've figured it out or not.