I highly recommend you to play through the story by yourselves, without referring to any walkthrough. Here I am posting an achievement guide just in case anyone has difficulties getting all achievements.
There are 10 achievements in total. Five of them are quite hard to miss since you just need to listen through the audio of each level once without playing with the progress bar. Three are achievements of different endings. Only two achievements need special actions and can be obtained using level select after finishing the game once.

To get these achievements, simply listen through the audio logs of each level without playing around with the progress bar at the first time. Then the achievements will pop and you can use those functions freely.

When asked 'who are you', choose 'No. 68' then choose the ashtray on the right side.

When asked 'who are you', choose any option other than 'No. 68' or 'detective' (worst ending?)

When asked 'who are you', choose 'No. 68' then choose the pills on the left side.



*Choose 'detective' to see an ending without new achievement

Listened to Emily humming a snatch of a song from end to end. Obtainable in level 5 (mental hospital); stay in the living room for Emily's whole song. You can use fast-fowarding.

Checked each room in the five maps. Missable rooms include bathroom on the top-right in level 3 (police station) and some small rooms in level 5 (mental hospital). You can use level select to do this; for me I re-entered level 3, entered the bathroom and the achievement popped without the level being solved again.

I first heard the game last month during GDC and first played it yesterday on PAX East. I love the game and purchased it immediately after its release and finished it in 5 hours (yup it's 7AM in the morning now in Boston). Unheard is different from any detective game I've played before, with the only sensory you rely on is your auditory. There's no murder weapon, no fingerprints, no solid proof. Listen carefully to every word because all you have are your ears. I really enjoy the game.

2 new achievements: Director and NEXT Case. Both are story related and cannot be missed.
Please refer to the DLC community guide by Bunny ·
DLC Answers (Spoilers)

Pops out when you get the right answers for the first and second questions.

Pops out when you solve the 3rd (final) question.