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