Here is the full list of all 30 Porcunipine achievements.
Win a Last Man Standing game without ever breaking your helmet
Play one minute in the Arena mode without collecting any skulls and dying
Play practice mode as every porcunipine
Win an Arena game against 3 bots
Visit every arena in the game
Reach 48 hours of play time
Finish an entire Last Man Standing game without dying
Win a team game without ever killing your teammates
Play as Blue porcunipine in Team Red or as Red porcunipine in Team Blue
Die inside the Pyramid
Make a 3 players combo kill in Last Man Standing and win the round
Kill all 4 players (yes, including yourself) with a single shot
Stand in the snow area for 15 seconds straight in the Ice Age level
Kill the Blue porcunipine 100 times
Kill the fastest wolverine
Play with 3 friends
Win a round of Last Man Standing without killing anyone
Make 2 close calls on different players with a single shot
Kill a player while dead
Stand still for 15 seconds
Kill 5 or more enemies with a single shot
Collect a total of 666 skulls in the practice mode
Win a game against a team of 3
Collect 500 skulls playing for team Red
Collect 500 skulls playing for team Blue
Win an Arena game with at least 10 skulls more than the other players
Kill a player 10 times by bouncing a shot off a rock
Activate switches 100 times in a round
Get stoned by a falling boulder at 4:20 pm
Earn every achievement in the game