Here is the full list of all 8 Clock Simulator achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Play continuously for 3 minutes.
Play continuously for 5 minutes.
Get 10 perfect taps in a row.
Get 5 perfect taps in a row.
Finish a round in under 1 second.
Get 10 perfect taps in one game.
Play continuously for 1 minute.
Get 5 perfect taps in one game.