Under the microscope: Gunbird & Mobile Light Force (Saturn, PlayStation)

Again!

Jun 04, 2025

In this edition I’m examining Gunbird, the vertical shooter from Psikyo. I found:

Four new cheats for the Saturn version: a test menu, invincibility, level skip, and frame advance.
One new cheat for the PlayStation (released as Mobile Light Force outside of Japan): invincibility.

The details are below!

This picture isn’t related to the cheat codes, but I like how the character select screen looks in this game.

Gunbird (Saturn)

In a previous edition I wrote about a patch that I made for Gunbird that grants access to the game’s Test mode. I’m revisiting Gunbird for this article because I found a cheat code that lets you access this test menu without a patch. Here’s the method:

Hold Start as the game is booting up. Release it once the Atlus video starts playing.
Enter this sequence during the Atlus video: B, Left, Up, Down, B, A, A, Down.

The Test Mode Main Menu screen should pop right up:

See the previous article for operation instructions.

I also found three other cheat codes. The first one enables NoDeath mode. You’ll need two controllers and possibly four hands for this:

At the Gunbird Press Start Button screen, hold X+Y+Z on both controllers.
Let this screen time out. The opening animation will start to play. Press Start to skip it.
Hold X+Y+Z on both controllers again.
Let the screen time out again. Press Start to return to it.
Hold X+Y+Z on both controllers a third time.

The NoDeath indicator will appear if you got it right:

As the name implies, this prevents you from dying if you get hit.

The next cheat code is similar:

At the Gunbird Press Start Button screen, hold L+R on both controllers.
Let this screen time out. The opening animation will start to play. Press Start to skip it.
Hold L+R on both controllers again.
Let the screen time out again. Press Start to return to it.
Hold L+R on both controllers a third time.

The Skip indicator will appear if you got it right:

You can now press L+R during gameplay to complete the stage you’re playing.

The last cheat code is a little bit different:

Hold Start as the game is booting up. Release it once the Atlus video starts playing.
Proceed to the Gunbird Press Start Button screen, then hold A+B+C on both controllers.

You’ll see the Pause indicator if you got it right:

During gameplay you can now hold L and press Z to pause the game and advance by one frame. Hold L and press Y to resume normal gameplay.

Technical details: One of the first things the game does (in the function at 06019244) is check whether you’re holding start. If you are, it sets the 4 byte flag at 060afce8.

If that flag is set, then the function at 0601b0f4 checks your input against one of four sequences:

B, Left, Up, Down, B, A, A, Down
B, Left, Up, Y, B, C, C, A
B, Left, Up, Up, A, Left, C, C
B, Left, Up, Left, B, B, B, X

Any one of them will activate the test menu. If you get one of the buttons right, the counter at 060b5224 increments. When it reaches 8, the function returns 1. This changes the game’s mode to 08, which corresponds to the test menu.

When the title screen is active, the function at 06024388 is checking controller 1 and controller 2 for identical button presses. When it finds one of L+R, X+Y+Z, or A+B+C, it updates a tracker (at 060b543c).

The Skip and NoDeath logic checks the tracker three times. The Pause logic checks it once if the “held Start at boot time” flag mentioned above is set.

Here are some Action Replay codes for all three effects:

160afcee 0001  # Pause cheat
160afd06 0001  # Skip cheat
160b5422 0001  # NoDeath cheat

Mobile Light Force (PlayStation)

Do the cheats from the Saturn version of Gunbird work on the PlayStation version? Answer: no. But I found one cheat that does work:

Let the Press Start Button screen time out.
Press L1+L2+R1+R2+Square during the opening scene and keep holding them. Press and release Start while still holding the other buttons.

You won’t get an indicator onscreen, but you’ll be invincible once gameplay starts:

This is equivalent to the NoDeath cheat on the Saturn version.

Technical details: The function at 80098640 (NTSC-U version) is checking for controller input. If it sees the relevant pattern (008f) on both controllers 1 and 2, it sets the flag at 80098640.

The corresponding Action Replay code should be:

800DF240 0001  # NoDeath cheat

Outro

You might be wondering: the earlier article also had patches for Strikers 1945 and Sengoku Blade. Are there similar cheats for those games? Good question — check back next week for an answer.

You might also be wondering: what on earth is going on with Mobile Light Force? Why was it released for the PlayStation so late (in 2003)? Why was the title screen changed to have unrelated characters on it? These are also good questions, but I have no idea what the answers are.

Many thanks to privateye for testing out the Action Replay codes above!

Rings of Saturn

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