Kill 50+ mutants with your Wii remote held sideways in one level to get an odd bonus of $1337.
Achievements
All the achievements in the game are listed in the Extra Contents menu (the extra videos, music, images, and 3D models). Simply perform the task required to unlock the item.
AutoShotgun Is All You Need
To get a consistent Goregasm combo, purchase and upgrade the autoshotgun to the maximum. All you need is one hit on most zombies to kill them, giving you one shot, one kill capability.
Bonus money
Kill at least fifty mutants in a level with your gun held sideways for a $1,337 bonus at the end of that level. Note: This can only be done once per game.
Defeating Carney Boss Nigel and Sebastian
At the beginning you will just have a gun. This works better when you have an upgraded automatic shotgun. Shoot the small head as much as possible until you get to the part where the clowns start flipping out. There is a brain in the bottom corner of the box where the first clowns come out to the Boss. Shoot the legs out from the under the clowns while flipping. They will start to crawl. When they are on the ground, attack the Boss.
Director's Cut mode
Successfully complete Story mode.
Dual Wield mode
Successfully complete Director's Cut mode to unlock single player Dual Wield mode in Story and Director's Cut modes. This allows one player to use two Wiimotes with a single health bar.
After Dual Wield mode is unlocked, you can use it in any other profile. Simply activate the Dual Wield mode in the profile that completed the game, then exit out and select a profile that has not completed the game.
Easy Goregasm combos
Purchase and upgrade the Autoshotgun to the maximum level. A single hit on most zombies will kill them.
Extra Mutants mode
Successfully complete Story mode to unlock extra mutants in Story mode.
Handcannon weapon
Successfully complete Story mode.
Minigun weapon
Successfully complete Director's Cut mode.
Money bonuses
Complete the indicated task to receive the indicated amount of money. Bonuses can only be unlocked once per saved game file. Once collected in Story mode or Director's Cut mode, the same bonus cannot be unlocked in the opposite mode.
Complete level 1 in Story mode: $500
Complete level 2 in Story mode: $1,000
Complete level 3 in Story mode: $500
Complete level 4 in Story mode: $500
Complete all levels in Story mode: $1,200
Complete level 1 in Director's Cut mode: $1,000
Complete level 2 in Director's Cut mode: $1,000
Level 1 score bonus: $5,000
Level 2 score bonus: $5,000
Level 3 score bonus: $5,000
Level 4 score bonus: $5,000
Level 5 score bonus: $5,000
Level 6 score bonus: $5,000
Level 7 score bonus: $5,000
Get first place on high score screen: $1,000
Get last place on high score screen: $200
Get 70 total leg shots: $250
Get 50 total head shots: $200
Reach 70% accuracy: $400
Kill 50 Mutants in a level with your gun held sideways: $1,337
Tailor the High Score
Tailor you high scores to rack in the bonus for "beating the high score". If you cannot top your high score in a stage any more, you will not earn money for buying guns in the shop.
The Lost Golden Brain
The infamous lost golden brain changes location, though this is not a glitch, the developers just decided to make achieving everything close to impossible. The lost golden brain appears as just a speck in the corner of the pool room on the far right side, it is found when you turn around after viewing the "experiments" and Isaac says "You're into some sick s**t man."