Here is the full list of all 10 The Room Three achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Complete The Room Three with the 'Lost' ending.
See every ending in The Room Three.
Complete The Room Three with the 'Released' ending.
Complete The Room Three with the 'Imprisoned' ending.
Complete The Room Three with the 'Escaped' ending.
Complete Chapter 5, ‘The Observatory’.
Complete Chapter 4, ‘The Workshop’.
Complete Chapter 3, ‘The Clock Tower’.
Complete Chapter 2, ‘The Lighthouse’.
Complete Chapter 1, 'The Proposition’.