Radial Fusion

Radial Fusion is a 2D retro-style orbital space arcade shooter. You defend the solar system from destruction by destroying enemy fusion weapons before they trigger runaway Radial Fusion.

Levels 1–6

The main game has six levels of increasing difficulty. You win a level by destroying all descending enemy fusion weapons (blue); you lose if a stable orbital enemy mine (red) or a descending enemy fusion weapon triggers Radial Fusion. The bonus level becomes available after you pass level 3. At the end of each level, the game saves your initials, high score, total player ships damaged and game time.

The green player ship uses a beam weapon to target descending fusion weapons and, from level 5, low-orbit enemy ships; at level 6 it can also target high-orbit enemy ships. The beam can fire when your ship is closely aligned radially with the star and its target. You can speed up or slow down, move between orbits, and adjust your position to stay aligned. If the ship turns blue, recharge its beam; the spacebar must be released while it charges. If the ship is completely red and disabled, press S to reactivate it. The number of replacement ships is infinite.

Enemies and hazards

The threats vary by level:

• Descending enemy fusion weapons (blue): These descend toward the star and trigger runaway Radial Fusion if they reach it. Colliding with one damages your ship.
• Stable orbital enemy mines (red): Appearing from level 2, mines fire an orbital plasma weapon if you stay too long in one orbit. Destroy them with your defense weapon or change orbit. A collision makes the mines fire lasers into the star, triggering runaway Radial Fusion; firing at a mine also makes it fire back and subtracts points.
• Charged yellow orbits: From level 3, entering one damages your ship but clears the orbit. Fire your orbital beam before entering to discharge it safely.
• Charged red orbits: From level 4, entering one disables the beam used against descending fusion weapons.
• Low-orbit enemy ships (yellow): From level 5, these fire a laser at your ship when it is radially aligned with the ship and star. Use your shield for protection.
• High-orbit enemy ships (purple): Appearing at level 6, these send a weapon toward the star that damages your ship on contact. Use your shield for protection.

At levels 5 and 6, pressing S also activates a temporary additional shield against low- and high-orbit enemy ships.

Bonus level

In the bonus level, you play until your ship is destroyed. Use its beam weapons to discharge low- and high-orbit enemy ships before they fire. Firing at an enemy that is not charging produces a feedback beam pulse and reduces your score. Enemy weapons charge faster as the round continues. The game saves your initials, high score and the low- and high-orbit enemy ships’ charge speeds for the bonus round.

The bonus level uses separate targeting beams for the two orbits: move the low-orbit target beam with the up and down arrows, and the high-orbit target beam with the left and right arrows. Fire the corresponding player-ship beam at the enemy that is charging.