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