Here is the full list of all 31 Shift Happens achievements.
Die in the level "103a: Push&Pull"
Splitting up doesn't get you anywhere
Finish the Grotto [Multiplayer]
Finish each Grotto-level with 75 coins and Bonus Object [Multiplayer]
"Steal" the chain-coin from your partner who did all the hard work [Multiplayer]
Finish the canyon stage [Multiplayer]
Collect all 75 coins and the bonus-object in each level in the canyon stage [Multiplayer]
Finish the forest stage [Multiplayer]
Collect all 75 coins and the bonus-object in each level in the forest stage [Multiplayer]
Collect all 75 coins and the bonus-object in each level (apart from the testchambers) in the laboratory stage [Multiplayer]
A "little" unfair distribution of coins [Multiplayer]
Finish the laboratory stage [Multiplayer]
Struggle yourself free! [Multiplayer]
Finish the laboratory stage [Singleplayer]
Collect all 75 coins and the bonus-object in each level (apart from the testchambers) in the laboratory stage [Singleplayer]
Finish the forest stage [Singleplayer]
Collect all 75 coins and the bonus-object in each level in the forest stage [Singleplayer]
Finish the canyon stage [Singleplayer]
Collect all 75 coins and the bonus-object in each level in the canyon stage [Singleplayer]
Finish the Grotto [Singleplayer]
Finish each Grotto-level with 75 coins and Bonus Object [Singleplayer]
Finish all levels (including bonuslevels) [Singleplayer]
Finish all levels (including bonuslevels) [Multiplayer]
Finish ALL levels with 75 coins and Bonus Object [Singleplayer]
Finish ALL levels with 75 coins and Bonus Object [Multiplayer]
"Push" a character over 8 meters.
Don't use the Shift in the level "102: Troubling Teamwork" [Singleplayer]
Throw a crate and let your partner catch it without dropping it to the ground [Multiplayer]
Get squished by a small crate with the big character