How do I earn the hidden achievement “Play it again Sam”?

Question

The Achievement wiki page states "Play all three parts on the piano all the way through."

What does this mean, and how do I obtain this achievement?

Answer 1

Once earned, the (more accurate) description of the achievement is: "Play an entire song on the piano with 3 players"

The criteria to get this achievement is:

• Play a mission with a piano in it
• Play with at least two other teammates (3-4 players)
• Play the piano synchronously with two teammates for approximately 60 seconds

Some easy steps to obtain the achievement:

1. Start the mission Manoir Moucharder with one person being the cleaner. Having a lookout is helpful too to avoid guards.
2. On the first floor there are three disguise kits: one in the north side of the house, one on the south-east side, and one right next to the piano in the middle. Have each player grab a disguise kit and meet behind the piano.
3. Have the cleaner knock out the guy at the piano, then coordinate with the other two people to begin playing on both sides of the cleaner at the same time.
4. Have all three people hold → on the piano (and don't let go) until each person gets the achievement. The disguises provide ample time for wandering guards to not notice you.