In the demo version, pressing the right mouse button multiple times (3x) takes you to the next level.

Level Codes:
Level 2: 1996903124397205
Level 3: 8863607123456789
Level 4: 3011964376678672
Level 5: 6063729666266297
Level 6: 6666660000000001
Level 7: 7707717727737747
Level 8: 1010101010101018
Level 9: 9876789876789876