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