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