Here is the full list of all 39 Pentagonal Saloon achievements.
Solve the light games
Collect a coin
Open the geometrical doors
Solve the geometrical puzzles
Collect the square card
Solve the puzzle at room-3
Solve the puzzle at room-4
Make all playing-cards visible
Collect a note
Get all confirmations from the screens
Locate the goblet
Solve the goblet puzzle
Collect the triangle card
Collect the circle card
Solve the puzzle
Fece the fist
Get the flamethrower
Free the ghost
Get wet
Get bitten by spider
Eat your chocolate
Catch your candies
Eat your lollipop
Let the sugars flaw
Collect your sugars