Everything on this page is read in the code; none of it has yet been seen in the emulator.
F1 stops the game and you can type. The password is kept in the last twelve keys (0xE500, p06:BEA2) and checked on resuming (p06:BF2F, table p06:BEF1, each key as row × 8 + position in the matrix):
| Password | What it does |
|---|---|
| DS 4 | one more CLASS star |
| ANTA WA ERAI | three more stars |
| INTRUDER | every ammunition maximum to 999 |
| ISOLATION | the ration maximum to 999 |
| HIRAKE GOMA | all eight cards |
F1 pause, F2 weapons, F3 equipment and F4 transceiver (p01:6F94). In the pause, F4 loads and F5 saves the game on tape: the header is ten 0xEA bytes and a six-letter name, followed by the 0x300 bytes at 0xCA00 and their sum (p15:B948). After GAME OVER, F5 goes on from the last checkpoint: there are 31, each a room and entrance pair (p06:BE64).
Only the P.BOMB hurts it, and only when the last 16 hits, each on one side or the other of its X, match p02:8D3B. When it breaks a countdown from 3000 starts (p01:757B), and leaving room 0xE2 at the top (p01:643A) leads to the ending.
| Item | What it does | Where |
|---|---|---|
| GOGGL | shows the beams | p15:BF22 |
| LIGHT | removes the darkness of rooms 0x7B-0x7D, 0xDC and 0xDD | p00:4ACB |
| DETEC | marks the mines | p03:AF9C |
| MASK | protects from the gas in 9 rooms | p02:8C05 |
| ARMOR | halves the damage of types 0x2B, 0x2F and 0x3A-0x3E | p02:8A05 |
| ANTID | cures the scorpion's poison | p01:7FAB |
| PARAC | saves you at the trapdoors | p02:93BF |
| BOX | inside it and still, the guards do not see Snake | p02:974F |
| SCOPE | turns on TELESCOPE MODE: you look into the next room | p01:7FDD |
Without the SILENCER, firing raises the alarm and brings reinforcements (p02:804F), except in 55 rooms (p02:806C).
Those of classes 2 to 9 want their card, CARD1 to CARD8, selected (p01:794D). Others open with punches, forty hits (p01:79E9), or with the P.BOMB (p01:7973).
Seven frequencies, from 120.13 to 120.91 (p00:490C). Some calls are only heard while sending (SEND) and others depending on what has happened: the CLASS, whether a text has been read or a game flag (p01:6A88).
Manuel Pazos published his disassembly of this same cartridge in 2017 (GuillianSeed/MetalGear). Here it has been used only as a reference, without taking anything from his code; the 235 rooms of this repository match his reference images point for point, and the enemy type names quoted are his. Thank you, Manuel, for a superb piece of work.