During gameplay, press ~ for the console window. Then enter any of the following "Codes": 

Code
 Effect
 
pikemon  
 Win Current Level
 
monsterbonus  
 Monster Fish Bonus Powerup
 
twominute  
 Two More Minutes Powerup
 
powercast  
 Power Cast Powerup
 
superpowercast  
 Super Power Cast Powerup
 
silentcast  
 Silent Cast
 
stealthboat  
 Stealth Boat Powerup
 
shallowboat  
 Shallow Boat Powerup
 
pikeflag  
 Pike Flag Powerup
 
bigpikeflag  
 Big Pike Flag Powerup
 
lunkerpikeflag  
 Lunker Pike Flag Powerup
 
manualcam  
 Toggle Manual Camera Movement
 
fps  
 Toggle Frame Rate
 
bonuslure  
 ???
 
skipcast  
 ???
 
metric  
 ???