Gradius NES

Gradius is Konami’s 1986 NES conversion of its 1985 arcade shoot-’em-up, piloting the Vic Viper starfighter through horizontally-scrolling stages against the Bacterion Empire. Its power-up system uses a meter of selectable upgrades — speed, missiles, lasers, and the signature Options that trail and mimic the ship’s movement — that you activate manually rather than picking up fixed items.

That gauge-based, player-timed power-up system became one of the shoot-’em-up genre’s most imitated mechanics, and its unforgiving rule that losing a life strips all accumulated upgrades at once set an influential — and notoriously punishing — difficulty standard that shaped how brutal the genre was allowed to be on home consoles.