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