Here is the full list of all 36 Gloom achievements.
A grander existence
An embryo of the cosmic way
Resilience is a virtue
A pillar of demented faith
A pillar of demented art
A place for expression and madness
A place for ascension
A mirror of null existence
A narrator of nightmares
One-of-a-kind weapon
An instrument of ascension
A false prophet of ill omens
A place for silence and emptiness
A ghastly tide of salvation
An agent of secrecy
A fallen deity of envy
A place for the shunned and forgotten
An orphan of spite
A place for the lost and demented
An embodiment of deific anger
You perished in a dream
The book in all its glory
Well that's just sadistic
No more dreaming, no more nightmares
You've got the hang of it
Must be routine at this point
Win in less than 12 minutes
Win in less than 8 minutes and 30 seconds
He had it coming
All for one
Three wins in a row
Ten wins in a row
A place for gloom
Most renowned of them all
Leo's blades and both eyes simultaneously
To retrieve what was once lost