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