Here is the full list of all 10 Apocryph: an old-school shooter achievements.
Slay the Guardian Titan.
Slay the Guardian Titan on Immortal And Eternal Reaper difficulty.
Die from colliding with world boundaries.
Find 10 Secrets.
Kill a total amount of 1000 monsters.
Reach The City Below
Enable a cheat code.
Die a total amount of 10 times.
Pick up a total amount of 100 items.
Die for the first time.