Death from Above: Get pushed into a seal cub by a bear, so you're probably gonna loose alot before you get this one. He charges you, you get hit any fly away, landing on a seal cub.
Walrus Terminator: All players must follow the pistol and shotgun only rule for it to work.
Evacuator: I'm quite sure this one doesn't work, I think I did it a long time ago but nothing happend. (shoot with pistol once on the activist and then 1 shot with the revolver on the cub, this works only on level 2 I think)
(Not 100% sure about these fact)