Here is the full list of all 64 King Arthur's Gold achievements.
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 a match
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
Join multiplayer
Join a modded server
Use chat
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!
Commit suicide
Go down with a sinking warboat
Switch teams
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