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