Here is the full list of all 14 BiT Evolution achievements.
Carry the first Spider Clam to the goal tape on level 3-11
Complete a level without ever entering the Realm of Code
Collect all of the pixels in the game
Complete 20 levels in the game's challenge mode
Defeat the game's final boss
Defeat the boss of World 4
Complete a level without killing any enemies (not even bats!)
Survive 30 seconds with the "death wall" in level 1-11
Defeat the boss of World 3
Defeat the boss of World 2
Obtain a gold star on any 10 levels
Find any hidden area within the game
Obtain a gold star on any level
Defeat the boss of World 1