Here is the full list of all 25 12 orbits achievements.
Arena practice: Score 40 points with a single player
Unlock all other achievements
Trails practice: Score 35 points with a single player and without ever touching a wall
Arena Practice: Score 26 points with a single player and without ever orbiting
Blizzard: Win a 1 vs 6 match while controlling no one but the solo player. No modifications.
Blizzard practice: Score 28 points with a single player
Blizzard practice: Score 20 points with a single player and without ever dodging
Multiball: Destroy all three of one team's goals within 12 seconds
Trails practice: Score 50 points with a single player
Arena practice: Score 30 points with a single player
Blizzard practice: Score 22 points with a single player
Arena: Play a whole game against 11 opponents without ever being eliminated. No modifications.
Orbs can be a little shy sometimes
Arena or Trails: With 2 or more players, color 50 spheres before a single player is eliminated
Trails: Hit 2 players with a single shot
Trails practice: Score 37 points with a single player
Trails practice: Score 25 points with a single player
Arena practice: Score 20 points with a single player
Blizzard practice: Score 16 points with a single player
Color 12 spheres with a single blast
Hit the player responsible for your elimination with one of your own spheres, before it becomes their color
Orbit with 12 players at the same time
Skip the countdown to start a new game in less than a second
Finish a game with an active modification
Use a single blast to trigger two more blasts