Here is the full list of all 11 King Randalls Party achievements.
Stay in the air for 10 seconds
Knocked over 50 ladders
Repaired 100 Ladders
Lose 10 times and let the King Throw a Party
Get Hit by 100 Arrows
Collapse 50 Blocks at the Same Time
Fall to Your Death 25 Times
Collide With the Top of the Map
Build a Ladder 25 Blocks High
Get hit 100 times.
Win 10 games, preventing the King from throwing a party.