Here is the full list of all 63 Earth Overclocked achievements.
Finish Earth Unleashed in the Scientist Suit
Defeat Elemental Meiun
Beat the final boss
Defeat the rare Jef
Defeat the rare Slendy
Finish a run in the Gym Suit
Finish a run in under 15 in-game minutes
Defeat Meteor Bob
Defeat a Sandstorm
Score 50,000 with the Gym Suit
Defeat the rare Benny
Score 200,000 points
Defeat the rare Chucab
Defeat the Blob Bros.
Finish a run in the Magnet Suit
Defeat Foreman Jack
Defeat a Wumbo Blob
Score 50,000 with the Magnet Suit
Defeat the special Gold Blob
Defeat a Yeti
Finish a run in the Ninja Suit
Defeat the Night Emperor
Score 50,000 with the Ninja Suit
Defeat a Crystal Heart
Defeat the Royal Dillos
Finish a run in the Scientist Suit
In the Scientist suit, complete a run without using the revive potion
Defeat Meiun
Delay the Apocalypse by 6 minutes in one run
Defeat Frozen Bones
Defeat the rare Mothguy
Defeat Zombakuto
Delay the Apocalypse by 4 minutes in one run
Defeat the Soul of Raynald
Delay the Apocalypse by 150 seconds in one run
Score 50,000 with the Scientist Suit
Defeat a Tree Monster
Finish Earth Unleashed in the Ninja Suit
Finish Earth Unleashed in the Gym Suit
Finish Earth Unleashed in the Magnet Suit
Collect all of the contents in the Mega Slot Chests
Beat the Time Empress
Buy the most expensive weapon from a merchant
Finish a run in the Birthday Suit
Use the Sheep weapon on an enemy
Finish Earth Unleashed in the Birthday Suit
Defeat Treebot
Score 50,000 with the Birthday Suit
Yep. (only need the Singleplayer ones)
Defeat Skeleking
Defeat a Bombcano
Defeat Mystery
Defeat Zombakuto BW
Run into the instant death spikes
Lose 50 runs
Finish a run in under 12 in-game minutes
Finish a run in under 10 in-game minutes
In the Ninja suit, defeat a boss without using either attack button
In the Magnet suit, have 15 hearts follow you at once
In the Gym suit, defeat a boss with both weapons at full weight
Defeat one of Meiun's Advocates
Take no damage in a run
Take no damage in a run in Earth Unleashed