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