Unlimited levels and 99 skill points:

Gain a level and wait for the screen with the perks 
to appear. Highlight the perk and click "Done" on 
the perk screen. However, click "Cancel" on the main
screen. Click back to the character screen and the
perk screen will appear again. Repeat these step to
gain unlimited levels and 99 skill points.

by unknown


Go in the inventory and then write the codes: 

irule - to get all weapons 
halloworld - to see all the map 
youhoo - to be invincible 

Submitted by leif.gud at mi.is