Here is the full list of all 50 Beat Blast achievements.
Have 6 or more enemies slowed, poisoned or stunned at the same time
Clear the first level without taking damage
Defeat Queen Bee
Block a laser with Riot Shield
Have six or more turrets active at a time
Defeat a boss using the Sword
Acquire a curse from the black market
Unlock ten abilities
Earn a timed reward
Die for the tenth time
Collect 30 sound pickups
Have a power note, offensive equipment and defensive equipment at the same time
Defeat the Sentinel
Defeat a boss with 1 heart remaining
Unlock your first ability
Die for the first time
Upgrade a power note
Acquire a legendary ability
Defeat the Giant Snake
Dodge through an enemy or an enemy projectile
Have all four note colours equipped to your song at once
Complete the tutorial
Participate in a competition
Defeat a boss in under 60 seconds in Compete mode
Get 10 or more stacks of a single passive ability
Acquire 24 or more notes in a single run
Buy everything in a store
Hold 500 or more bits at one time
Unlock everything
Defeat Meg&Byte
Defeat the Seed
Defeat your first enraged boss
Defeat every boss
Defeat every enraged boss
Clear the first two levels without taking damage
Clear the first three levels without taking damage
Clear all four levels without taking damage
Play with the Escape Artist and Power Saw abilities at the same time
Play with the Fortify, Riot Shield and Barrier abilities at the same time
Play with the Sword and Riot Shield abilities at the same time
Destroy ten or more enemies with a single Bazooka shot
Chain 3 or more dodges together
Find your way out
Defeat the Seed with a difficulty rating of 1.0 or higher
Defeat the Seed with Automelodic and Plagued challenge modifiers active
Defeat the Seed with the Operation and Super Spot challenge modifiers active without touching a wall
Defeat the Seed with Spiral Bullets
Defeat a boss or miniboss while under the effects of a shrine
Unlock every challenge modifier in Play mode
Defeat an elite enemy with a single critical hit