Level Codes:

Level 2: BLOOD BATH
Level 3: CLEANSING FIRE
Level 4: SCORCHED EARTH
Level 5: THUNDER STRIKE
Level 6: LIGHTNING RAID
Level 7: BLIZZARD STORM
Level 8: DEATH OR GLORY

The following cheats can be used during gameplay:

KITCHENER  = units are invulnerable
MONEYBAGS  = money
ADVANCING  = level can be ended with joystick fire button
THE LEGION = all cheats at once