After Janine says "Hey it's Christmas" and Eliot says "Yeah, It's my payday", go back to the bank and use Eliots ATM card to withdraw another $2000.(his christmas bonus).
$20000 in 20 minutes
Make sure that Eliot has his axe or stun rod, about and about 3 or 4 clips in his hand gun(this is also easier if Doggs has his rail gun). Go to the Bait and tackle shop and kill the creatures that attack you then go out side and do the full axe combo on the monster in the green t-shirt right outside the tackle shop door. This will kill him. You will then attract the attention of a monster wearing a white t-shirt this monster leaps at you but gives you $250 kill him away from the water and go in to the tackle shop and repeat. If you have about 20 small hassys you can get about $20000(no typo) in about 20 minutes. This is easier if you can lay down the full axe combo on the green guy because if he is still alive he and the leaper will team up on you. If things are getting ugly then switch to Doggs and Blast them with your rail gun. This takes a bit of practice but the rewards are great.
200 Hassy Drinks
Successfully complete and save the game. Then, start a new game from the saved game file to have 200 Hassy Drinks (100 small and 100 large) in the inventory. This should allow the game to be played with near-invincibility, and the additional bonus of not having to buy any other health items. Additionally, any money left from the last game will also be available in the new game.
All Weapons
Save a game that has been successfully completed in under five hours. Then start a new game from the saved game file to begin with all weapons and nine rounds of ammunition.
Bank card passcodes
Go to the Bank Of Kimra (across the street from Rat's Place) and enter the passcode for one of the following bank cards to access that account with the corresponding amount of money:
Successfully complete the game on the "Hard" difficulty setting. In this mode, the characters will have big eyes and a big lip, and the weapon they are carrying will be visible.
Heat-seeking laser gun
Successfully complete the game twice and save the game. Then, start a new game from the saved game file to receive a heat-seeking laser gun, which is not available in any shop or vending-machine. It fires four heat-seeking lasers.
Hidden artwork
Place the game disc in a PC compatible CD-ROM drive to find .BMP images and two short voice samples in .WAV format in the "Omake" directory.
Lab card passcode
Obtain the Lab card from Rat's Place, then return to Janean. Eliot will give Janean the Lab card and she will ask for the passcode, enter "0513" as the passcode.
Mad Mode
Successfully complete the game three times and save the game. Then, start a new game from the saved game file. The phrase "Mad Mode" will appear next to the health bar. In this mode 200 Hassy Drinks, all weapons (including the ray gun), and full ammunition will be available.