Secret passwords:
All passwords here except the last one are not secret, but this is exactly full set of passwords and its destinations.
AXOLOTL - Level 8 (1st Boss)
BLUTEN - Level 9 (2nd World)
CHIMERA - Level 16 (2nd Boss)
DEWLAP - Level 17 (3rd World)
ELYTRON - Level 24 (3rd Boss)
GILA - Level 25 (4th World)
HYDRA - Level 32 (4th Boss)
IBEX - Level 33 (5th World)
JEDOCH - Top of the Tower
KURZER - Level 24 (Descent)
MINORCA - Level 23 (Descent)
PANGOLIN - Level 16 (Descent)
REMORA - Level 15 (Descent)
TROKEN - Level 09 (Descent)
SCARAB - Level 08 (Descent)
ZAHNBELA - Final Boss
ANCIENT - Stage Select