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