Dead Rising/Psychopaths

Throughout the game, Frank will encounter Psychopaths - survivors of the zombie outbreak who aren't in the mental state to be rescued. Often, they've taken other Survivors hostage and will attempt to kill them; your only course of action is to take them out first.

The list below is in more or less chronological order, and may contain spoilers.

The Convicts
The convicts are unique among Psychopaths - they'll respawn at midnight each night, with the exception of September 22, and they don't count towards the Psycho Collector, Psycho Taker or Punisher Achievements.

Adam MacIntyre
This clown went insane after seeing the children he was entertaining being killed by the zombies. He now obsesses over the Space Ride that he worked at, and will not allow anyone to stop it.

At the start of the fight, Adam is on the far side of the Space Ride track. Head shots are effective against him, but the best tactic is to run out of the Space Ride station away from Adam and onto the walkways around Paradise Plaza. His dual chainsaws are capable of doing a lot of damage, so you want to keep your distance and shoot the balloons he inflates before he throws them at you; they'll damage him much more than almost any of your weapons can, with the bonus of distracting him for a few seconds to land another couple of shots.

When the fight is over, stop the Space Ride to save Greg, who will open a shortcut for you between the Wonderland Plaza and Paradise Plaza bathrooms.