Here is the full list of all 36 Gloom achievements.
A grander existence
An embryo of the cosmic way
No more dreaming, no more nightmares
A pillar of demented faith
A place for ascension
A narrator of nightmares
A pillar of demented art
A mirror of null existence
An instrument of ascension
He had it coming
An embodiment of deific anger
Resilience is a virtue
All for one
A place for expression and madness
An agent of secrecy
One-of-a-kind weapon
A place for silence and emptiness
A ghastly tide of salvation
A place for the shunned and forgotten
An orphan of spite
A false prophet of ill omens
A place for the lost and demented
A fallen deity of envy
You perished in a dream
The book in all its glory
Well that's just sadistic
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
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