Under the Microscope: Alien Trilogy & Ghen War

In this edition, I find some long-unknown passwords for Alien Trilogy, and one of them is surprisingly rude. Here’s the comprehensive list of passwords with new ones highlighted:

I also examine Ghen War and come up with a handful of new cheat codes. Here’s the full list of the ones that game accepts:

Two games this time! There are more details below.

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Alien Trilogy

As of this writing, GameFAQs lists three special passwords for the Saturn version of Alien Trilogy:

• F1SH1NGF0RGVNS for “all weapons”
• F1LLMYP0CK1TS for “unlimited ammunition”
• FVNKYG1BB0N for “invincibility”

For PlayStation it only has one:

• 1G0TP1NK8C1DB00TS0N for “Cheat Mode”

Is that everything? I decided to investigate.

I used my usual memory snapshot diff trick to find that the first three Saturn passwords above set bits in the 4 byte field at 0604b650 (I’m using the NTSC-U version). That led me to the function at 06007466, which gets called when you enter a password.

Here’s part of Ghidra’s decompilation of that function, with my annotations:

There’s an unknown password!

The decode_passwords_01 function is at 06007438. It reads a series of values starting at 0604d4d0. The lengths match up for the last three known passwords, so they seem to be scrambled using some fairly simple scheme.

1. LI\\T/QKW.LF/I].K\\W2
2. Y.LW.QXY/MXIQL2
3. Y.SSRFO/\\T.KL2
4. YIQTFX.]]/Q2

Indeed, the decode function is straightforward: each byte of the encoded password is XOR-ed with the value 1f. When do that to the strings above, the plaintext passwords pop right out:

1. SVCK0NTH1SY0VB1TCH
2. F1SH1NGF0RGVNS
3. F1LLMYP0CK1TS
3. FVNKYG1BB0N

The first one is the unknown one, and now I can kind of see why they didn’t put it into game magazines.

This is indeed the password for the missing Cheat menu. After you enter it, a new Cheats menu appears on the title screen. You can use it to select your starting stage and toggle the other cheat effects.

For completeness, here are the missing corresponding passwords for the PlayStation version. Three of these are unknown!

Cheat menu:             1G0TP1NK8C1DB00TS0N
Gimme weapons*:         DY1NGT0N1GHT
Unlimited ammunition*:  B0X0VTR1CKS
Player indestructible*: 0BL1V10NTR1PT0F1N1SH0FF

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Ghen War

The English language Internet knows one cheat code for this game: GameFAQs, IGN, and ConsoleDatabase each list the “Cheat mode” code that you can enter on the pause screen.

The Japanese language Internet knows a couple of additional cheats: this site lists a “Stage select” code and a “Show credits” code that you can enter at the mode select screen.

Let’s get everything into one place. The NTSC-U version of the game has a function at 0601de0c that listens for button presses on the mode select screen. It’s looking for three sequences, and you have to be holding Start during each of them:

Stage select: Right, Right, L, Down, L, A, Y, Right, R
Credits: Left, Right, A, R, Y, C, R, Right, Left
Movies*: Down, Right, Right, A, L, L, R, Right, Right, L, Down

The stage select and credits codes match the ones on the Japanese cheat site:

The movies code is new! It plays the live action FMVs one after the other.

The function at 0601dc68 is listening for button presses when the game is paused. It’s also looking for three sequences:

Cheat mode: A, R, Down, Right, Up, A, L
Complete mission*: Down, A, Y, B, Y, Right, B, Y, Right
Change perspective*: B, A, R, B, R, A, Left, L

Two new codes here! “Complete mission” does what you think it would — the stage you’re on ends, and the next one begins.

“Change perspective” is pretty interesting! If you press X+Y+Z during gameplay, the camera will start tracking something other than you — usually the enemies that are wandering around. You can see yourself from their viewpoint, if they’re near you.

If you hold Z and press C during gameplay, the camera will track your projectile until it collides with something — very strange!

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Outro

You’re welcome and encouraged to submit these cheat codes to your favorite reference site. Spread the word!

For more new codes for old games, see my archive.

*This post is syndicated from Rings of Saturn, Bo’s reverse engineering blog.