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