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