Here is the full list of all 40 The Walking Dead: Season 2 achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Completed Episode 5: "No Going Back"
Found your way through.
Reached the terminus.
Made it through to morning.
Stopped for the night.
Reached the other side.
Took a breather.
Made it out alive.
Completed Episode 4: "Amid the Ruins"
Got back on the road.
Survived the attack.
Reached the museum.
Found the Observation Deck.
Returned to the meeting place.
Learned new survival skills.
Got separated from the group.
Completed Episode 3: "In Harm's Way"
Gave what you got.
Invited some friends into the compound.
Got beaten down.
Committed larceny.
Made it through your first day.
Witnessed a murder.
Arrived at your new home.
Completed Episode 2: "A House Divided"
Settled things with a new friend.
Helped someone through a difficult time.
Talked to a stranger.
Left the cabin.
Found a way across the water.
Met someone on a bridge.
Made it to the ski lodge.
Completed Episode 1: "All That Remains"
Found a campsite.
Met new people.
Arrived at the cabin.
Got what you needed.
Took care of yourself.
Headed out with the group.
Arrived at the shore.