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