Here is the full list of all 26 Just Shapes Beats achievements.
Complete a challenge with Rank A or higher on all levels
Complete Story
Beat 'Final Boss' (Story mode)
Beat 'Close To Me' Boss (Story mode)
Beat 'Lycanthropy' Boss (Story mode)
Beat 'Barracuda' Boss (Story mode)
Beat 'New Game' Boss (Story mode)
Beat tutorial Boss (Story mode)
Complete a level without dashing (Challenge mode)
Obtain 10 Rank B
Complete a playlist of 10 songs or more
Obtain 10 Rank A
Complete a playlist of all bosses
Obtain 20 Rank A
Obtain Rank S without dashing
Obtain 15 Rank S
Dash 1000 times (Challenge mode)
Dash 2500 times (Challenge mode)
Rescue 50 friends (Challenge mode)
Rescue 250 friends (Challenge mode)
Complete 25 challenges
Complete 50 challenges
Complete 100 challenges
Get 2000 Beat Points
Get 7500 Beat Points
Get 25000 Beat Points