Here is the full list of all 47 Gift of Parthax achievements.
Defeat 500 enemies
Complete the tutorial
First death
Open an empty chest
Complete summer season
Defeat Feykir
Find all objects for a season
Collect 10 health potions
Open a chest with riches
Complete spring season
Defeat Mounorian
Casting first ally spell
Adding 4 of same kind of rune to a spell, first time
Defeat 100 enemies
Destroy all breakable objects for a season
Purchasing first rune
Read the introduction story
Defeat 1000 enemies
Complete fall season
Complete winter season
Complete the entire game without a single death
Died 3 times
Died 10 times
Collect 2.000 gold
Collect 5.000 gold
Collect 10.000 gold
Collect 20.000 gold
Collect 10 mana potions
Collect 50 mana potions
Collect 99 mana potions
Collect 50 health potions
Collect 99 health potions
Defeat Nereus
Defeat Hrist
Defeat Parthax
Complete a challenge with only fire spells equiped
Complete a challenge with only earth spells equiped
Complete a challenge with only frost spells equiped
Complete a challenge with only Arcane spells equiped
Complete entire game using only fire as primary element
Transform 10 enemies into chickens
Purchase all runes available
Damage more than 5 enemies with the effect of an explosive rune
Gain light magic
Gain blood magic
After Parthax' death
Complete blood moon season