Catenoid

1. 
   Event Horizon

   Move a piece from one board to the other
   36%
2. 
   Spaghettification

   Land a piece inside the wormhole
   36%
3. 
   Long-Distance Relationship

   Capture a piece on the other board
   23%
4. 
   Pentagon Papers

   Land a piece on a pentagon (nexus) cell
   36%
5. 
   Knight Errant

   Jump a knight across the wormhole
   23%
6. 
   Tourist

   Cross between boards 10 times
   0.0%
7. 
   Frequent Flyer

   Cross between boards 100 times
   0.0%
8. 
   Interdimensional Commuter

   Cross between boards 1,000 times
   0.0%
9. 
   Holy Hell

   Capture en passant
   0.0%
10. 
    Castle in Space

    Castle your king
    18%
11. 
    Ascension

    Promote a pawn
    23%
12. 
    Underachiever

    Promote a pawn to anything but a queen
    0.0%
13. 
    Promoted Abroad

    Promote a pawn on the board it didn't start on
    18%
14. 
    It Ain't Eazy Bein' Cheezy

    Control three queens at once
    14%
15. 
    A New Dimension

    Win your first game
    27%
16. 
    Silicon Sacrifice

    Defeat the computer
    9.0%
17. 
    Battle Royale

    Win a 4-player free-for-all
    9.0%
18. 
    Better Together

    Win a 4-player team game
    0.0%
19. 
    Executioner

    Eliminate a player in a 4-player game
    18%
20. 
    Clock Management

    Win on time
    0.0%
21. 
    Checkmate from Another World

    Deliver checkmate with a move that crossed boards
    0.0%
22. 
    Blitzkrieg

    Deliver checkmate within 20 moves
    0.0%
23. 
    Pacifist Crown

    Win by checkmate having captured 3 pieces or fewer
    9.0%
24. 
    Matchmade

    Complete a Quickplay match
    18%
25. 
    Redecorator

    Win a game with every UI theme
    0.0%
26. 
    Graduate

    Complete the tutorial
    0.0%

Names, descriptions and icons are the game’s own, as Steam publishes them; the share is how many owners have unlocked each, from Steam's global figures for 26 of them.