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