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