Here is the full list of all 31 Space Otter Charlie achievements.
Built your first Lazor. Pew, Pew!
Turned on the lights aboard H.M.S. Tomcat.
Defeated the A.R.E.S. aboard H.M.S. Tomcat.
Made a bank-shot to open a door on Valencia Station.
Defeated the ghost of Captain Gregg on Valencia Station.
Escaped firey death on Pallas Station.
Built the Spinshot and escaped Tornado Labs.
Power up the Verituf MEGA Bot!
Defeat A.R.E.S. v2.0 with the Verituf MegaBot.
Recruited a friend to help colonize space.
Talked to 4 rescued colonists aboard the R.A.F.T.
Beamed every colonist aboard the R.A.F.T.
Unlocked all the levels on the galaxy map.
Upgraded one of your weapons.
Upgraded the Lazor, Reflector, and Missile Launcher.
Upgraded your suit with 4 thrust, shield, or slide upgrades.
Built a custom space suit.
Built 5 custom space suits.
Completed 2 full data log entries.
Collect all the Otter Fact data log entries.
Got crushed to death. Ouch.
Discovered 10 hidden areas.
Collected 80 space crystals.
Investigated Project 1138 in Erebus labs. Lived to tell the tale.
Destroyed 200 boulders.
Killed 15 enemies with reflected shots.
Destroyed 30 enemies without using a gun.
Destroyed 3 Pixel Cat spawners.
Start a new single player game after having finished the game.
Finished 15 matches of "So Urchin!" multiplayer mode.
Finished 10 matches of "Furry Fury" multiplayer mode.