Here is the full list of all 17 Obulis achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Complete the level "Dark Forest III Ultra"
Collect all 347 1/2 stars in the game.
Complete the level "Garden V Ultra"
Complete the level "Pharaoh's Tomb VII Ultra"
Find all 3 tiles to complete the Blood Stone.
Complete the level "Antiquity XI Ultra"
Complete the level "Clock Tower VIII Ultra"
Complete the level "Desert VIII Ultra"
Complete the level "Dungeon V Ultra"
Complete the level "Pond III Ultra"
Complete the level "Pond X Ultra"
Complete the level "Pharaoh's Tomb I Ultra"
Complete the level "Waterfall XI Ultra"
Find all 3 tiles to complete the Earth Stone.
Complete the level "Gnarly Vines V Ultra"
Complete the level "Windmill I Ultra"
Find all 3 tiles to complete the Sun Stone.