Here is the full list of all 21 3x64 achievements.
The base game contains 20 achievements, and there is 1 DLC pack containing 1 achievements.
Destroy at least 5 iron blocks using TNT or Big TNT
Destroy 4 or more blocks in one row
Destroy line during invisibility
Send your first replay to the leaderboard
Use at least 9 powerups in one game
Achieve combo 6 or higher
Destroy the threat block just before activation
Craft at least 4 powerups in one game
Reach 1500 points
Finish arkanoid minigame without failure
Clear the game board at level 10 or higher
Place yourself in the top ten of the leaderboards
Destroy at least 15 blocks at once by gravity change
Destroy a threat block using a powerup
Use all types of powerups (standard and crafted) during single game
Reach 500 points without changing gravity
Use your first crafted powerup
Achieve level 100
Destroy 7 blocks in one line (without using powerups)
Destroy all irons at level 20 or higher (Simple Mode)
Reach rank 20 (Coming soon in Anniversary Update 1.3)