Under the microscope: Blam! Machinehead (PlayStation)

These codes are not quite safe for work

Machinehead (also known as Blam! Machinehead) is a first-person shooter from Core Design, the studio most famous for the original Tomb Raider games.

Aficionados have long known that it’s possible to cheat at this game – the same three codes have been listed on IGN’s page for the game since at least 1999. Each one involves pressing some sequence of Circle and L1 and the main menu:

Infinite Ammo: At the main menu, press Circle, Circle, Circle, Circle, L1, Circle, L1, L1, Circle, L1, Circle, L1, L1, Circle, L1, Circle, L1, L1, L1, L1.

Infinite Energy: At the main menu, press Circle, L1, L1, L1, Circle, L1, Circle, Circle, L1, Circle, Circle, Circle, L1, L1, L1, L1, L1, Circle, Circle, L1.

Level Select: At the main menu, press L1, Circle, L1, L1, L1, Circle, Circle, Circle, Circle, L1, L1, Circle, Circle, L1, Circle, L1, Circle, Circle, Circle, Circle. Use R1 and R2 to choose your starting level.

It’s easy to locate data related to these codes in a memory snapshot – there are plain text strings that refer to them:

800be468 "LEVEL SELECT"
800be4b4 "INFINITE ENERGY"
800be4c4 "INFINITE AMMO"

Given these, it’s surprising that this game’s other codes haven’t been discovered in 30 years. Here’s a string in the same neighborhood:

800be484 "MANDELBROT MODE"

Ghidra shows that the function at 8001cf3c reads this string. That is the cheat code listener – it compares player input to pre-specified sequences. The sequences encode Circle as 0x07 and L1 as 0x01.

For Mandelbrot Mode, we have:

Circle, L1, L1, Circle,
L1, Circle, Circle, Circle,
Circle, L1, Circle, L1,
L1, L1, Circle, Circle,
Circle, L1, Circle, Circle

You’ll hear a sound effect after entering it. Start the game to see a cool Mandelbrot fractal viewer. The D-pad changes the view and colors – here’s a video of it in action:

Here’s another string with the name of a cheat effect:

800be478 "NANO SPERMS"

The button sequence is:

L1, Circle, Circle, L1,
L1, L1, Circle, Circle,
Circle, Circle, Circle, Circle,
L1, Circle, L1, L1,
Circle, Circle, L1, Circle,
Circle, L1, L1, Circle,
L1

Here’s a video of what it does:

(Michael Bluth voice) I don’t know what I expected…

The next new code is associated with the string PROFILER:

L1, Circle, Circle, Circle,
Circle, L1, Circle, Circle,
L1, Circle, Circle, L1
L1, L1, L1, Circle,
Circle, L1, L1, Circle

It puts a resource meter onscreen:

The fourth new code’s label is ALTERNATIVE CREDITS:

Circle, Circle, Circle, L1,
L1, L1, Circle, Circle,
L1, Circle, Circle,
Circle, L1, Circle, L1,
Circle, Circle, L1, Circle,
Circle

If you finish the game after entering it, you will indeed get alternative credits that poke fun at the people who worked on the game. Not all of the humor has aged well, but complaining that your bosses are “fucking helpless” is timeless:

The game recognizes two more sequences that don’t seem to work properly. VRAM EXPLORER ENABLED will pop up if you enter this sequence:

L1, Circle, L1, L1,
Circle, L1, Circle, Circle,
L1, Circle, Circle, Circle,
Circle, Circle, L1,
Circle, L1, L1, Circle,
L1

However, you can’t do much with it. Holding R1 on Controller 2 will make the game stutter, but there’s no other effect.

This code pops up the message JEZZA MODE ENABLED:

Circle, L1, Circle, L1,
Circle, Circle, Circle, L1,
Circle, L1, L1, L1,
Circle, L1, Circle, L1,
L1, Circle, L1, Circle,
Circle, Circle, Circle, Circle,
L1

The flag at 800bf73d gets set after the sequence is entered, but no game code seems to read it. Maybe “Jezza” refers to Core Design founder Jeremy Heath-Smith?

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Outro

For more on games from Core Design, see the articles on Swagman, Fighting Force, Fighting Force 2, and Actua Golf.

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