Frank West arrives at Wonderland Plaza to find the Space Rider roller coaster malfunctioning at an uncontrollable speed. As he investigates the control panel, a demented clown, Adam MacIntyre, appears with two chainsaws in his hands. He shares his story of how he was an entertainer for the children that came to mall before the outbreak.
When the zombie outbreak at Willamette occurred, Adam went insane after seeing children being killed by zombies. He warns Frank not to stop the Space Rider or the zombies will return, and he then attacks Frank.
After Adam is defeated, he collapses and falls on top of his chainsaws, which kill him. Frank retrieves an ID card from his body, and is able to use it to stop the Space Rider, freeing Greg Simpson, who has been caught on the ride. Greg then shows him to a secret passageway in the restrooms in Wonderland Plaza, which leads to Paradise Plaza.
When Frank is a distance from Adam, Adam will blow a balloon full of poison gas.
Adam will spin his chainsaw.
Adam will slice Frank with his chainsaw.
When Frank is near Adam will blow fire.
When Frank is a reasonable distance from Adam, he will throw knives.
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 second floor walkways around Wonderland Plaza. His dual small chainsaws are capable of doing a lot of damage, so Frank needs to keep a distance and shoot the balloons he inflates before he throws them at Frank; his balloons will damage him much more than almost any of your weapons can, with the bonus of stunning him for a few seconds to allow for a couple of more shots.
One strategy is to drop down into the children's play area below, and kick the toy cubes at Adam, using first-person view for increased accuracy. They will knock him over and allow Frank to get a couple of shots in before he retaliates with fire breath. Therefore, run after attacking Adam. Frank can also pick up one of the gumball machines and throw it at him.
The Sledgehammer's primary attack is good, as is using the Katana, Battle Axe or Sword. The Sickle and Cleaver are also useful as they have short attack animations and can hit Adam multiple times before he recovers and starts to block.
Another strategy in to grab a big chainsaw from Crislip's at around 8:00pm. The problem is that it is a two handed weapon, so every time a zombie grabs Frank, he drops the chainsaw.
Large Machine Gun
Arguably the lazy way to defeat him is to rip the LMG off the back of the convict's jeep and as soon as the fight starts level it at the psychotic clown and fire. He will block it preventing most of the damage but emptying the clip will leave him with only about an eigth of his life bar making the fight trivial with any other fire arm and just dodging till he gets ready to throw a knife or blow up a balloon, a couple more rounds from most weapons will kill him after that. If you can hit him with the LMG without him blocking however it will get 3-4 rounds in and take half the rest of the clip to kill him even with his blocking.