Here is the full list of all 19 AudioSurf achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Dethrone a friend from a global scoreboard.
Beat a friend's score less than 15 min. after they earn it.
Earn Clean Finish and Gold 3 times in a row.
Stealth and collect every color block. 3 min minimum.
10000 points per minute. 3 minute minimum.
Earn triple a gold medal requirement. 2 min minimum.
Earn Gold without overfilling. 2 min minimum.
Using Ninja Mono, earn Stealth. 3 min minimum.
Using Ninja Mono, earn Stealth. 7 min minimum.
Using Ninja Mono, earn Stealth. 11 min minimum.
30000 points per minute. 3 minute minimum.
Collect matches in 4 colors simultaneously.
Collect a chain reaction of 7 white blocks.
Score 17000 points in a single match.
Finish Clean, Gold before finish, hit last block, elite only.
Collect a match of 24 blocks.
Fill all columns within 15 seconds. No greys. No matches.
Turn 21 blocks red with a single paint.
Make a candy stripe.