Invasion from Jupiter in Space

Invasion from Jupiter is a side-scrolling shooter submitted to js13kGames 2021. The premise is pure arcade pulp: unusual sightings in the sky above Earth turn out to be invaders from Jupiter, and you assemble as a top pilot to defend the planet and launch a counter-attack on Jupiter itself.

The game spans six levels — Earth, space, a first boss, Jupiter, space again, and a final boss — giving it a structured campaign arc that many jam entries lack. The developer openly notes the difficulty is set quite high, which is both a honesty signal and a warning: this is a shooter that respects the genre's roots and expects you to earn your progress. The side-scrolling format with enormous end-of-level bosses is a deliberate homage to classic arcade shooters, and fitting that vision into 13 kilobytes is the real feat.

It earned top recognition in the 2021 competition. For fans of hard side-scrollers with boss rhythms, Invasion from Jupiter delivers a complete, no-hand-holding experience.

Invasion from Jupiter uses keyboard controls:

• WASD or Arrow keys to move • K to fire your weapon • L to use the tractor beam

The tractor beam is your secondary tool — use it to grab pickups or manipulate objects that pure firepower cannot reach. The six levels follow a pattern of survival stages punctuated by boss encounters; learn each boss's attack pattern before pushing for damage.

Strategy: the difficulty is intentionally high. Do not rush — clear screens methodically and conserve your tractor beam for moments when you are overwhelmed. Boss fights reward patience: observe the pattern, find the safe zones, and strike during recovery windows.