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