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