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