Here is the full list of all 47 Gift of Parthax achievements.
Complete spring season
Defeat Mounorian
First death
Casting first ally spell
Collect 10 mana potions
Collect 10 health potions
Destroy all breakable objects for a season
Defeat 100 enemies
Adding 4 of same kind of rune to a spell, first time
Purchasing first rune
Defeat 500 enemies
Defeat 1000 enemies
Complete summer season
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 50 mana potions
Collect 99 mana potions
Collect 50 health potions
Collect 99 health potions
Defeat Feykir
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
Complete the tutorial
Gain light magic
Gain blood magic
Read the introduction story
After Parthax' death
Find all objects for a season
Open a chest with riches
Open an empty chest
Complete blood moon season