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