Here is the full list of all 14 Weird Hat Fight achievements.
Play the game with 4 players
Completed 100 matches
Completed 50 matches
Completed 10 matches
Played on all maps
Played Orbit map
Played Propeller map
Played Arena map
Collected 100 hats
Collected 50 hats
Collected 10 hats
Collected 1 hat
Completed 1 match
Played Crafts map