On the title screen (option screen), type "DENTRASSI". You will be presented with a new option screen. Use the left and right cursor keys to select the starting level. During play press ']' to skip levels.
05- "HANUKKAH"
10- "JOENK"
15- "GENCON"
20- "LUNKWILL"
25- "OPAL"
30- "TROLL"
35- "VRANX"