Just a reminder these "cheat" codes offer direct access to levels 2-10:
Level 2 ("All Jolly Good Fun"): EJK
Level 3 ("Robots on the Rampage"): WHU
Level 4 ("All about the Timing"): ZFQ
Level 5 ("The Mausoleum"): ECY
Level 6
("This is Just Weird"): EET
Level 7 ("Who Left a Pyramid Here?"): FJH
Level 8 ("The Battlements"): HZO
Level 9
("Hero Worship"): RYN
Level 10 ("This is the End!"): GIL
Just select option 3 from the main menu and enter your chosen three letter code.