Here is the full list of all 13 Serious Scramblers achievements.
Complete the first level.
Unlock any character for the first time.
Crush 5 consecutive enemies without landing.
Crush 10 consecutive enemies without landing.
Clear level 1 to 8.
Clear level 9 to 14.
Defeat Mid-Boss.
Clear level 21 to 24.
Clear level 25 to 26.
Defeat Final-Boss.
Defeat the final boss using Unicorn.
Defeat the final boss without dying.
Die 100 times. Every failure is a celebration!