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