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