Zaxxon

Zaxxon is a 1982 ColecoVision game from Coleco, originally released in arcades in 1982, catalogued here for 5 defining game mechanics.

ColecoVision1982Originally Arcade 1982Complexity 24/1002D IsometricPopular

Zaxxon is a 1981 isometric scrolling shooter developed by Sega; the ColecoVision port was a flagship title. (via Wikipedia)

The genre Zaxxon helped define

Isometric shooter. Diagonal isometric scrolling created an early illusion of 3D depth.

Scrolling MovementTraversalWorld scrolls in one or two axes as the player moves or time passes; player exists within an advancing boundary.
Contact DamageCombatTouching an enemy or environmental hazard deals damage to the player without any explicit attack trigger from either party.
Projectile SystemCombatPrimary player-versus-enemy interaction is firing and/or dodging discrete moving objects.
Ammo ManagementResourceWeapons have finite ammunition tracked separately from weapon ownership; running dry forces behavioral change.
Lives SystemResourcePlayer has a finite number of attempts; losing all lives resets progress to a defined point or ends the game.

Each mechanic links to how to build it in Godot, with the retro games that share it.