Here is the full list of all 22 Galacide achievements.
Get 750 bit clears in a level
Destroy 3 enemies in a bomb's explosion
Beat the snake boss on any difficulty
Reach a combo of 25
Complete a Multi-match
Reach a combo of 15
Get 500 kills in a level
Get a clear of 10 or more, 10 times.
Beat Level 1. Unlocks the Freighter ship.
Get a combo of 5
Get 1 million points in Endless Play
Get 500,000 points in Endless Play
Beat the boss and get to threat level 6 in Endless Play. Unlocks the Phase ship.
Get to threat level 10 in Endless Play
Clear 25,000 Bits.
Kill 10,000 Enemies.
Complete 10 multi-matches
Travel a total distance of 500,000 parsecs.
Kill 3 enemies in one phase ship charge shot.
Store 3 bombs in the freighter's cargo.
Clear puzzle mode
Beat level 6. Unlocks the military ship.