Here is the full list of all 27 Little Red Rocket Ship achievements.
Start a new game.
Defeat the Megabeamer Mk. I.
Defeat the Cyber Scuttler.
Defeat the Granfalloon.
Try Endless mode for the first time.
Destroy 15 Shooters.
Destroy 4 Marauders.
Defeat PENTAFORCE.
Encounter the Rival for the first time.
Watch a Ghoul come back to life.
Spot an invisible Poltergeist.
Reach 80% corruption.
Reflect a green bullet.
Find out what happens when you freeze something and then blast it with plasma shots.
Take a swig of the "house special."
Use a drink before heading into a level.
Fulfill the Pensive Cadet's request.
Change your ship's color.
Change your plasma pistol's shot color.
Destroy 6 Derechos.
Defeat the Swarm Mother.
Hook an enemy and use it to destroy another enemy.
Reach the 5th unique tier in Endless mode.
Take a relaxing dip in the local hot tub.
Defeat the Granfalloon in one hit.
Deliver Vanessa's letter.
Claim your first bounty from YLW.