Here is the full list of all 27 ORE achievements.
Do yourself a seppuku.
Die. Die a lot. In a single level.
Ten tons of fun. On top of you.
Heal. Heal a lot. In a single level.
Save a friend from a hungry enemy.
Push a bug off a ledge. That simple.
Get spicy, then get your friends spicy, too.
Finish a level without your weapons getting tired and hot.
You've passed basic training.
One man (or woman) wolf pack.
Stick with what you're good at, I guess?
You beat the big bad and saved the planet as just a duo.
You beat the big bad and saved the planet as a triplet.
Kill the boss and save the planet with three of your bestest friends.
You beat the boss and saved the planet solo.
Beat the boss with plenty of attempts left to spare.
You almost lost your best friend. Good thing you're a professional at this stuff.
You're a friend murderer. You're a bad person. But so are we for giving you friendly-fire, so good job, I guess?
You killed that one nice and SLOW.
You journeyed to the center of the planet. Good luck!
You discovered the secrets hidden in Pandora Drifts.
You discovered the secrets hidden in Glacier Depot.
You discovered the secrets hidden in Radiant Coast.
You discovered the secrets hidden in Searing Lava Fields.
You discovered the secrets hidden in The Foundry.
You're a very big spender.
You drained those hotspots of a massive amount of money.