Here is the full list of all 68 Runbow achievements.
Play with 9 unique costumes/characters
Play 1000 multiplayer rounds
Beat the boss in the Island map
Beat 10 Adventure levels with a friend
Play a level in each Adventure map
Get 3 medals in 15 Adventure levels
Be stunned when you get the trophy
Unlock every guest character
Play a lot
Get the Mimicry power-up 10 times
Do 20 taunts in one game and win
Go through 20 portals
Get the Lightning power-up 10 times
Play King of the Hill
Win when an enemy has 1 second or less
30 seconds in pull zones
Play 500 multiplayer rounds
Die 100 times in the Bowhemoth
Beat all levels in the Forest map
Get 3 medals in 10 Adventure levels
Beat the boss in the Forest map
Do 10 Butt Pounds
Play 300 multiplayer rounds
30 seconds in push zones
Get the Swapper power-up 10 times
Land 5 Super Punches
Play Arena
Land 20 hits in one game and win
Land the most hits & get the least wins in a game
Play a game without anyone else scoring
Win a tie-breaker
Play 10 multiplayer games
Taunt 20 times
Play 100 multiplayer rounds
Run a total of 42,195 meters
Beat 100 enemies
Break 30 breakable blocks
Play 7 multiplayer games
Play 5 multiplayer games
Play 2 multiplayer games
Jump upwards 1609 meters
Get killed by a laser
Fall to your death 20 times
Land one of each type of attack
Spend more than 3 minutes in the air
Play a Run game
Set the Fun type to Maximum
Set the Fun type to Kawaii
3 medal all levels in the Forest map
Beat all levels in the Island map
3 medal all levels in the Island map
Beat the boss in the Prison map
Beat all levels in the Prison map
3 medal all levels in the Prison map
Beat the boss in the Nightmare map
Beat all levels in the Nightmare map
3 medal all levels in the Nightmare map
Beat adventure mode and defeat Satura
Beat all levels in Adventure mode
3 medal all levels in Adventure mode
Unlock all gallery content
Beat the Bowhemoth
Beat the Bowhemoth in 60 deaths or 60 minutes
Beat the Bowhemoth in 10 deaths or 20 minutes
Get the "Everyone Gets a Title" title
Defeat Plunto
Beat all of Out of This World
3 medal all of Out of This World