Here is the full list of all 14 198X achievements.
Reach level MAX in Kill Screen
Complete the Kill Screen maze using only super effective attacks
Complete Beating Heart without dying or using pick-ups
Complete The Runaway without a single collision
Watch the end credits all the way through - thank you backers!
Complete 198X
Complete Kill Screen
Complete Shadowplay
Complete The Runaway
Complete Out of the Void
Complete Beating Heart
Complete Shadowplay without taking damage
Collect all power-ups in Shadowplay
Destroy every enemy in Out of the Void without losing a life