Here is the full list of all 24 YamaYama achievements.
Play through all the gamemodes at least once.
Collect 15 points without dropping the Platypus/Flamingo.
Humiliate your opponents in a single gamemode.
Get the jello right before it disappears in Defend The Jello.
FatSuit another player through the teleportation tunnel.
Electrocute opponents 10 times in one round in Prom Queen.
Collect all the power up packages in one gamemode.
Win at sudden death.
Collect 20 power up packages.
Win a match.
Steal more than 10 jellos from a specific opponent in Jello in my Belly.
Get 5 double kills.
FatSuit enemy players 50 times.
FatSuit 100 times.
Get 5 after death kills.
Get 200 Points.
Winning 50 single gamemodes.
Winning a gamemode after losing at least three in a row.
Win 10 matches.
Win over 80% of the gamemodes in a full game.
Win all the gamemodes in a full game.
Survive until the round timer ends in Snake 6110.
Destroy two players at once in Firecracker.
Be the only one to Catch The Pig 3 times in a row.