Full list of all 25 Trombone Champ achievements. It takes around 4-5 hours to unlock all of the achievements in the base game on Windows.
The base game contains 21 achievements, and there are 2 DLC packs containing 4 achievements.
Meet a Mysterious Friend
Receive an "S" score on fifteen tracks
Unlock a Sound Set
Play at least 20 tracks
Receive an "S" score on ten tracks
Receive an "S" score on five tracks
Meet Tootmaster Tom
Receive an "S" score on one track
Develop an enormous brain full of facts
Get a sack
Receive an "S" score on twenty or more tracks
Abstain from tooting
Meet Bassmaster Ben
Unlock a trombone color
Unlock all trombone colors
Unlock all Sound Sets
Get 50 Tromboner Cards
Turd your last Mozart card
Abstain from sound completely
Express your love of baboons
Become the Trombone Champ of Legend
Receive an "S" score on twenty-five or more tracks
Receive an "S" score on thirty or more tracks