Here is the full list of all 19 Big Crown: Showdown achievements.
Complete your first game
Be the last one alive but don't cross the finishing line
Purchase your first hat
Purchase all of the hats
Collect your first coin
Join a custom game
Knock 1000 objects off the track
Get your first knock-out
Complete a Local Multiplayer match
Complete an Online Multiplayer match
Make a custom game
Run a Marathon (26.2 miles)
Complete a round without punching
Play with 4 people locally
Play with 4 people online
Collect all of the coins from a treasure chest
Get your first shield deflection knock-out
Knock the Knight's TV into the portal
Win your first game