Here is the full list of all 33 Runner3 achievements.
Unlock EVERYTHING!
Finish all 9 Impossible Levels!
Got 'em All!
Collect all Golds and Gems and finish an Impossible Level!
Buy a bunch of new digs!
Get all the Gildans!
Defeat the Jungle Ruins' Boss!
Go exploring in the Retro World. Maybe you'll find a cute secret?
Defeat The Caves' Bosses!
Buy a bunch of Capes!
Defeat The Great Outdoors' Boss!
Get all your friends over for some GRILLINS!
Collect all the Narrator's Puppetshow Puppets!
Witness something creepy.
Better out than in...
Get a Perfect in each Standard Level in any World!
Invite a friend to the BBQ!
Get a Special in each Standard Level in any World!
Make it to the end of an Impossible Level!
Bonk the Timbletot!
Defeat Machineland's Boss!
Defeat Spookyland's Bosses!
Head off the Beaten Path...
Checkpoints? Who needs 'em!
Defeat Foodland's Boss!
Get a Special+!
Get a Special+ and a Perfect+ in any Level!
Buy a bunch of Accessories!
Get a Special!
Get a Special AND a Perfect in any one level!
Get a Special, a Perfect, and one Bullseye in any Level!
Get a Perfect!
Get a Perfect+!