Order Butters to heal up Wendy to receive a Superhero Patch. After that, use Nagasaki to bring down the drawbridge.
There are two ways to enter the castle. First is through the front door. Use the alien probe to reach the walkway. From there you can teleport in front of the puddle to lure the two guards and knock them out. Now, teleport again to the walkway and turn off the generator. You can then smash the gates open to reach inside.
The second method involves sneaking inside. Go to the right and destroy the barricade to reach the item bag by the tree. Head to the left of that tree and shrink your size to enter the hole.
Once inside, heal the gnome for him to knock out the rat. Now shoot the lighter and use your Cup-a-Spell to defeat the rat. Loot the item bag next to it as well.
Now you can either destroy the floor to the left or take the pipe to the right. The path to the left will bring you behind the barricade but with enemies waiting. The pipe to the right will allow you to sneak to the upper balcony. If you want to loot the items however, you can just simply beat the sh*t out of the enemies.
Climb the ladder to reach the second level. There will be multiple nazi zombies here with their cats so before destroying the barricade, wait for the other nazi zombie to return to his position then shoot the tire to the upper right to knock him out and his kitty. Now take out all the enemies in the room.
After clearing them out, hit the cracked part of the platform then follow it up to Nagasaki. Once done, wait for the pirates to lower the ladder for you. Climb up next.
After the scene, blow up the firecracker using your Dragonshout and to knock out the cyclops. Ike will become your friend by doing this. Head to the right and blow up the tower using Nagasaki. Loot the chest and turn the wheel to raise the gate a bit.
Head to the left this time and teleport on the balcony. Shoot the lamp in the second tower then use Cup-a-Spell to blow the tower and the enemies out. Teleport to the wheel and turn it afterward. Enter the fortress next.
Once inside, Craig will pull up the third cow. While he's doing this, shoot the lamp on the left window and blow it up to allow Kyle inside. Next, use Nagasaki on the window to the right to let Ike in. Blow up the chains to drop the second cow. After that, you have to beat up Craig and the remaining cow(s).
After taking out the cow, Craig will clone himself. Keep attacking the one in the center and ignore the others until you defeat him. Loot Craig's body then loot the chest to the left as well before taking the stairs.
After the scene, you have no choice but to shrink yourself and pull the snuke out of Mr. Slave's ass. If you leave the area, the snuke will detonate and end your game.
You'll have to relive Lemmiwinks' adventure. Continue and clear the path. Once you've reached the condom, destroy it and beware of the mutant bacteria that will attack you.
Continue forth until you run into a broken fuse. Have Stan use Sparky to pee on the fuse to blow it up. Continue to the right and you'll encounter some feces and a nazi zombie bacteria. Wait for it to go under the inflamed organ then shoot the organ to kill it. Now use to alien probe to get past the barricade.
Move along to find Mr. Hat (and register him as a friend for some reason) Continue to the right and use Nagasaki to blow up the billiards ball. Continue to the next to the next area.
Walk to the right and you'll find a phone. Once it rings, Big Gay Al will be added to your friends list. Defeat the bacteria to get a new weapon then loot the item bag to the right. Continue to the left to find a flashlight. You have to fix the batteries below then press the light on to drive away the bat.
Loot the chest to the left then climb up. You'll encounter the Sparrow Prince and you have to beat him afterward. He will summon a couple of nazi zombie bacteria.
After defeating him, continue to the right and use Nagasaki to create a path. Go to the left and use the alien probe to reach the vibrator's switch. Turn it on to clear the path.
Continue to the right and defeat two more soldiers. Once done, you'll reach the trigger. Set Jimmy as your buddy then loot the item bag first to the right. Order Jimmy to activate the button then examine the trigger to start another abortion mini-game.
After successfully disarming the snuke, you'll be let out of Mr. Slave. Catatafish, Frog King and the Sparrow Prince will be added to your friends list.
Continue to the left and north to reach the throne room. You now have to fight the reanimated Chef. Once he's almost dead, he will attempt to bite you. Press the displayed buttons to resist. After that, Clyde will burn Chef. Block his attack and use your fart to blow him away.
Watch the following scenes and the mission will be complete afterward.