Sub-Level 1: 83 Aliens, 3 Eggs, 1 Facehugger, 2 Predators = 89 enemies

Sub-Level 2: 76 Aliens, 5 Eggs, 3 Facehuggers (found in Med lab only) 1 Predator = 85 enemies

Sub-Level 3: 49 Aliens

Sub-Level 4: 60 Aliens, 1 Predator, 6 Facehuggers (found in Med lab only), 23 Eggs = 90 enemies

Sub-Level 5: 54 Aliens, 26 Eggs, 3 Predators = 83 enemies

Alien Ship: 50 Aliens, 42 Eggs, 5 Facehuggers, 1 Queen = 98 enemies

Predator Ship: 9 Predators

Air-Duct 1B: 10 Aliens (This is a self-contained vent found only in Sub-level 1)

Air-Duct 2B: 10 Aliens

Air-Duct 3B: 5 Aliens

Air-Duct 3C: 5 Aliens (This is a self-contained vent found only in Sub-level 3 Canteen security area)

Air-Duct 4B: 10 Aliens

Air-Duct 4C: 10 Aliens (This is a self-contained vent found only in Sub-level 4. This vent is used to get card 6)

Air-Duct 5B: 10 Aliens

Air-Duct 5C: 10 Aliens (This is a self-contained vent found only in Sub-level 5. This vent is used to access part two of level 5 and to access Alien ship.)

Grand total is 573 enemies