Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Bear Necessities (30 points): Complete the Story Mode.
Bear Faced Cheek (10 points): Achieve a 10x Combo bonus (not achievable in Multiplayer).
Teddy Bear (10 points): Get an A grade for a Story Mode Chapter.
Brainy Bear (10 points): Get an AA grade in 10 Puzzle Mode levels.
Never Leave A Bear Behind (30 points): Collect all the snowmen and break the cages in Story Mode.
Housing Slump (10 points): Destroy 50 trapper generators.
No Bears Were Harmed (10 points): Complete a Chapter in Story Mode without losing a life.
The Right To Bear Arms (10 points): Kill a trapper of each type (not achievable in Multiplayer).
Trophy Bear (20 points): Collect all 10 extra life pick-ups.
Smarter Than The Average Bear (30 points): Complete the Puzzle Mode.

Additionally, there are two secret achievements:

Long Shot (15 points): Kill a trapper with a sliding block over 15 grid squares away.
Roller Bear (15 points): Kill all the trappers on a boat level by only using the barrels.