In order to achieve Big Boss rank, you need to meet the following requirements:

-Difficulty: Original
-Play Time: Under 45 minutes - Game Timer can be paused by going into Data Save/Load menu
-Number of Saves: No Limit
-Number of Continues: 0
-Number of Alerts: 8 (Unavoidable)
-Number of Enemies killed: 0
-Number of Rations used: max 1
-Special Items: Not Used

Floor 1 (Left)
- Card1 - Gasmask - Pistol

Floor 3
- Plastic - Card2 - Rockets - Box - Grenade Launcher (4x Prisoner)

Floor 1 (Right)
- 2x Prisoner - SMG - Get Arrested

Basement
- Recover Gear - Card3 - max out G launcher ammo 30 - Uniform - Plastic - BombSuit

Floor 2
- Prisoner(Left) - Prisoner(Right 2x) - Parachute

Roof
- Max out missiles 10

Floor 1 (Center)
- Card4 - Prisoner - Mines max 15

Outside
- Max out Plastic Explosives(Left Truck) 15

Floor 1
- Antenna

Roof
- Prisoner - Card5

Basement
- Prisoner 2x - Card6

Floor 2
- Prisoner 2x - Rocket Launcher (call 120.48 near door)

Basement
- Restock RL ammo 30 - Max out Plastic Explosives

Floor 2
- Card7 - Compass (call 120.48 near door)

Optionally SAVE GAME after elevator

Basement
- Oxygen tank

Building 2 - Floor 1
- Max RL ammo - Card8

Building 3 - Basement
- Prisoner - RR, LR, LL, RL, LR, RL, RL, RR