Here is the full list of all 31 Pummel Party achievements.
Control over 50% of the area in 'Elemental Escalation'
Steal the last gift in a players pile in 'Grifting Gifts'
Survive in 'Breaking Blocks' for 60 seconds
Score over 5 in 'Bouncing Balls'
Get a 5 player kill sreak in 'Speedy Sabers'
Get launched off screen in 'Tunneling Tanks'
Knock off 5 players in one game of 'Snowy Spin'
Get your first goal
Survive for at least 50 seconds in 'Sorcerers Sprint'
Collect 40 keys in 'Winter Maze'
Win your first minigame
Complete 'Slippery Sprint' without falling in the water
Start your first game
Win your first game
Take no damage in 'Searing Spotlights' minigame
Accidentally blew yourself up in the 'Strategic Shockwave' minigame
Hit three players with the remote control eggplant
Skewer three players with the rocket skewer item
Place first in every minigame
Place last in every minigame
Get a double kill in 'Barn Brawl'
Survive for 50 seconds in 'Bullet Barrage'
As the lightning holder kill every other player in 'Thunderous Trench'
Knockout 10 players in one game of 'Explosive Exchange'
Complete 'Rusty Racers' without falling off the track
Got hit by the train in 'Temporal Trails'
Find the treasure in 'Sandy Search'
Died in 'Acidic Atoll' throwing a barrel
Win 'Magma & Mages' without taking damage
Complete 'Gift Grab' without collecting coal