Here is the full list of all 21 Button Frenzy achievements.
[Frenzy Mode] Remain in chain mode for two unbroken minutes.
[Frenzy Mode] Spend an unbroken 60 seconds in chain mode.
[Recall Mode] Successfully clear fifty 7 button sequences.
Use a popular cheat code on the main menu.
[Recall Mode] Successfully clear an 8 button sequence.
[Frenzy Mode] Survive for three minutes in Hard or Extreme difficulty.
[Frenzy Mode] Survive for 60 seconds in Hard or Extreme difficulty
[Recall Mode] Earn a x10 score multiplier.
[Frenzy Mode] Reach a x50 chain.
[Frenzy Mode] Clear 10 lines in a row and earn the fast completion bonus for each.
[Frenzy Mode] Clear 10 lines in 20 seconds with no mistakes.
[Frenzy Mode] Reach an APM (Actions per Minute) rate of 200.
[Frenzy Mode] Start on easy mode and reach Extreme difficulty in one run.
[Frenzy Mode] Reach a x100 chain.
[Frenzy Mode] Enter chain mode 51 times.
[Frenzy Mode] Clear 1000 lines.
Play the game between 00:00 and 05:00.
Play the game for an hour in one sitting.
Rack up one million correct button inputs.
Place 3rd or higher on a friends leaderboard
[Frenzy Mode] Enter chain mode 500 times.