At the 'Main' menu Select the 'Password' option and enter the following passwords to enable the corresponding effect in the game.

Medieval Exhibit Complete:
Enter the code FZ0T3!4P

Ice Age Exhibit Complete:
Enter the code L4RG42D3

Final Fight! Complete:
Enter the code 61Q9N1NH

Haunted House Complete:
Enter the code V4T18HFV

Unlock Workshop 1 Sun-level (Level 1):
Enter the code 0Q2Q8?CX

Unlock Workshop 2 Sun-level (Level 1):
Enter the code ?W9G12L6

Level 1 Complete:
Enter the code LJL7FW?R

Ride #1 Complete (level 2):
Enter the code 5RPRJRFV

Ride #2 Complete (level 3):
Enter the code X?6?VZBK

Ride #3 Complete:
Enter the code W8K1Z8PR

Sewers Complete (level 2):
Enter the code 8QNWMK0

Cookie Foctory Complete (level 2):
Enter the code K3VPZX8T

Unlock Sewer Sub-Level (level 2):
Enter the code FFPZFB!R

Unlock Circus Tent (level 3):
Enter the code THBLCL!R

Unlock Haunted House Sub-Level (level 3):
Enter the code FPB7NB2H

Unlock Ice Age Exhibit sub-level (level 4):
Enter the code ZZ0?KSL6

Unlock Medieval Exhibit Sub-Level (level 4):
Enter the code BXMZFM?R

Trap #1 Complete (Fred Mini-Game):
Enter the code 1WKCPCT8

Trap #2 Complete (Fred Mini-Game):
Enter the code 9BHV?8TM

Trap #3 Complete (Fred Mini-Game):
Enter the code 2PVX17QP

Mystery #1 Solved (Velma Mini-Game):
Enter the code 1Q0QQTCX

Mystery #2 Solved (Velma Mini-Game):
Enter the code HCHV7W?R

Mystery #3 Solved (Velma Mini-Game):
Enter the code !WJW?9SM

Mystery #4 Solved (Velma Mini-Game):
Enter the code X9G1Z9NR

Defeat The Guitar Ghoul:
Enter the code RX1FRS96

Defeat Caveman:
Enter the code XRG0Z9NR

Defeat Zen Tuo (level 2):
Enter the code !4QLDLJ0

Fight The Caveman:
Enter the code SF6NQF0X

Fight The Guitar Ghoul:
Enter the code W!5?VXCK