Here is the full list of all 21 Overloop achievements.
Discover a miracle
Pay respect
Defeat Douglas Infinity
Get killed by a giant cube
Say goodbye to Dennis
Get killed by a spring
Free Julia
get killed by a circular saw
Find rebels
Survive in the Factory
Die under the wheels of the Wonder Train
Hear Tommy out
Clone yourself 100 times
Get killed by any bullet
Get killed by squashing
You was't careful with a chandelier
Get killed by an energetic field
Get killed by a wall
Commit a suicide
Get killed by a laser
Find a crystal in your apartment