Here is the full list of all 64 King Arthur's Gold achievements.
Win a match
Switch teams
Join a modded server
Use chat
Join multiplayer
Commit suicide
Get 50 kills
Get 500 kills
Get 5000 kills
Get a bomb kill as an archer or builder
Get 5 kills with the drill
Get 50 stomp kills
Kill whole enemy team in TDM (at least 3 players)
Remain the last player alive in a TDM match
Blow yourself up as well as the enemy using a bomb
Kill the enemy flag carrier 10 times
Get a kill with each class in the same round
Run over an enemy with a vehicle
Kill someone using a fire arrow
Get a kill by launching a boulder from a catapult
Kill a player with a boulder 5 times
Get a kill on an enemy while dead
Kill an enemy with a tamed shark
Get a kill while on fire
Kill 3 people with 1 bomb
Kill 5 enemies with 1 keg
Get killed with an arrow 20 times
Get killed with a sword 20 times
Get killed with a pickaxe 20 times
Win 10 matches
Win 100 matches
Cap 5 flags
Cap 20 flags
Return your team's flag 5 times
Return your team's flag 20 times
Take 10 halls
Take 40 halls
Save the Princess
Kill the Princess
Complete 10 Challenge mode maps
Ride your tamed bison
Use all animals in game
Use water arrows 20 times
Use fire ammo 20 times
Get launched from a catapult 20 times
Launch another player from a catapult 20 times
Test the air-speed velocity of a laden chicken
Catapult a shark
Defuse a mine
Ride in every vehicle
Carry 4 burgers in your backpack at a time
Carry all 4 kinds of arrows
Take a nap in a quarters
Eat a flower
Sushi!
Go down with a sinking warboat
Heal an ally with a burger
Man them!
Capture 5 warboats
Steal an enemy's mine
Make love, not war
Design and arrange a shrub
Buy something at an enemy shop
Reach 500 coins at a time