Here is the full list of all 34 Eyes in the Dark achievements.
Clear an entire zone without taking any damage.
Successfully complete Act III.
Have at least 1000 sparks in a single run.
Kill a guardian without jumping.
Successfully defeat Hermitor.
Successfully defeat Wormitor.
Buy all 3 items offered in the shop.
Successfully defeat Blobor.
Kill a guardian without using the slingshot.
Successfully complete Act II.
Successfully defeat Mothor.
Successfully defeat Stingor.
Successfully defeat Arachnor & Snipor.
Successfully complete Act I.
Kill a guardian without using dodge.
Successfully defeat Hiveor.
Successfully defeat Broodor.
Successfully defeat Insector.
Complete the tutorial.
Complete a 9 zone run in under 45 minutes.
Complete a 9 zone run without equipping any items.
Unlock the entire bookshelf.
Successfully complete Act IV.
Fully upgrade all 3 item categories.
Scrap more than 50 items during a single run.
Finish a custom 9 zone run with at least 3 anomalies.
Kill 50 guardians.
Kill 200 guardians.
Complete a 9 zone run without using a single projectile.
Complete a 9 zone run without upgrading a single weapon category.
Complete a 9 zone run without picking up a flashlight module and/or upgrade.
Complete a 9 zone run without picking up a projectile module and/or upgrade.
Complete a 9 zone run without picking up a gadget module and/or upgrade.
Play the hidden tune in the Entrance Hall.