Mechanic · progression · shoot 'em up

Power-up meter

A bar of upgrades where pickups move a cursor and a button buys the upgrade under it.

stubAlso: power meter, Gradius meter, selection bar, capsule barUpdated 2026-10-21
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A power-up meter lets the player choose upgrades instead of taking them as they come. In Gradius on the NES each capsule moves a cursor along six slots, wrapping after the last, and a button press buys the lit one. Some slots refuse a second purchase1.

  • CursorGradius (1985). Six slots from Speed Up to ?; capsules move the cursor and a button buys the lit slot.1

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Mentioned in

Games

GameYearHowNote
Gradius1985Cursorsix slots from Speed Up to ?; capsules move the cursor and a button buys the lit slot
Every claim about this mechanic, by game (1)
Gradius 1985In the US NES Gradius each capsule moves the meter's cursor one slot along six, back to the first after the sixth, and a press of the power-up button buys the lit slot and clears the cursor. Taking the slots in the bar's order, Speed Up adds 1 to a speed count; Missile can be bought once; Double and Laser write 2 or 1 to one shared byte, so each replaces the other; Option adds 1 up to 2; and ? sets a shield counter to 5 when it's 0. A slot that can't be bought leaves the cursor where it is.Code

References

  1. ^ abIn the US NES Gradius each capsule moves the meter's cursor one slot along six, back to the first after the sixth, and a press of the power-up button buys the lit slot and clears the cursor. Taking the slots in the bar's order, Speed Up adds 1 to a speed count; Missile can be bought once; Double and Laser write 2 or 1 to one shared byte, so each replaces the other; Option adds 1 up to 2; and ? sets a shield counter to 5 when it's 0. A slot that can't be bought leaves the cursor where it is.Code“Gradius (USA)”
    How we know

    In the cartridge (“Gradius (USA)”): $894B-$8973, a capsule: increment the cursor at $42; at 7, set it back to 1; $8974-$89E2: on bit `$40` of the player's button byte, jump through a seven-entry table by $42 (0 does nothing). Slot 1 increments $40 with no check; slot 2 increments $41 only if it's 0; slots 3 and 4 store 2 and 1 to $44 unless it already holds that value; slot 5 increments $45 only below 2; slot 6 stores 5 to $46 only if it's 0. Each purchase stores 0 to $42 and calls $EC1E with `$0E`; each refusal returns first.. We don't reproduce the bytes.

    Checked against the evidence by its author, an AI model, 2026-10-21.

    Checked by a second AI model, 2026-10-21.

    In the claim ledger

Sources

Code