Here is the full list of all 13 Firebird achievements.
You left Zavodgrad and started your journey.
You left the Polar Star, on the border of the land of men.
You survived the Road of Bones.
You defeated Koschei.
You made it to the end of the world and faced the gods.
You made it to the gas station with your gas tank more than half full.
You made it to Vassilissa's village with your truck intact.
You learned the barman's name.
You helped Ivan choose the correct plant at Baba Yaga's house on the first try.
You found the egg without lighting more than two flares.
You made it to the gas station with more than 3 units of money.
You finished your journey.
You've been to every destination on the map.