Destroy Space Aliens achievements

Defeat the Hopper Boss in the Catacombs

Defeat the Space Alien Lord in the Keep

Defeat the Floater Boss in the Library

Defeat the Dragon Boss in the Caverns

Defeat the Lander Boss in the Watchtower

Triumph against a Boss Space Alien for the first time.

Sequence break out of the first segment of the game

Finish the game (Best Ending) in under 2 hours

Give in to Vengeance (Worst Ending)

Complete the game without destroying all of the Space Aliens (Normal Ending)

Destroy all of the Space Aliens (Best Ending)

Finish the game (Best Ending) without collecting Health, Damage, or Defense Ups