Here is the full list of all 18 Poker Night 2 achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Purchase a deck.
Win Claptrap's bounty item.
Purchase a drink.
Purchase a set of chips.
Win a tournament.
Win a hand.
Purchase a felt.
Activate the Borderlands deck, felt, and chips simultaneously.
Activate the Sam & Max deck, felt, and chips simultaneously.
Activate the Portal deck, felt, and chips simultaneously.
Win Sam's bounty item.
Win GLaDOS's bounty item.
Achieve a lifetime balance of one million dollars.
Unlock all decks, felts, and chips.
Activate the Venture Brothers deck, felt, and chips simultaneously.
Activate the Army of Darkness deck, felt, and chips simultaneously.
Win Brock's bounty item.
Win Ash's bounty item.