Level Codes:
Level 1: MANTIDS
Level 2: CICADAS
Level 3: PSYLLIDS
Level 4: KAVERNS
Level 5: SATYRID
Level 6: LYCAENID
Level 7: PYRALID
Level 8: NOCTUID

Cheats (type during gameplay):
"MERCURY" = auto-flight
"JUPITER" = unlimited time
"MARS"    = weapon select
"PLUTO"   = unlimited ammo