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