In which video game are Bacterions the enemy?

Bacterions are the enemy in the video game Gradius.

Released by Konami in 1985, Gradius is a horizontally scrolling shoot-’em-up in which the player pilots the Vic Viper spacecraft. The mission is to defend the planet Gradius against the Bacterians, an alien enemy force often described as an empire or civilization in the series’ story material.

The game’s signature mechanic is its power meter. Destroyed enemies can release capsules, and collecting one moves a selector along the meter. The player chooses when to activate upgrades such as speed, missiles, double shots, lasers, shields, and Options—small craft that mirror the Vic Viper’s firepower.

The wording can cause confusion because Bacterian or Bacterion is also used for the broader enemy faction and for recurring villains in later games. Gradius is therefore the expected canonical answer, even though the Bacterians appear throughout the wider Gradius series. The original game also helped establish Konami’s recurring “Destroy the core!” boss encounters.