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