Here is the full list of all 12 Braid achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Travel all the way across World 4.
Travel all the way across World 5.
Travel all the way across World 6.
Fit together all the world 4 puzzle pieces and align the puzzle in its frame.
Fit together all the world 5 puzzle pieces and align the puzzle in its frame.
Fit together all the world 6 puzzle pieces and align the puzzle in its frame.
Complete the game.
Complete a full speed run, beating the challenge time.
Travel all the way across World 3.
Fit together all the world 3 puzzle pieces and align the puzzle in its frame.
Travel all the way across World 2.
Fit together all the world 2 puzzle pieces and align the puzzle in its frame.