I’ll try my best for a list.
-Get all the functionality in first. Such as; movement, jumpscares, doors, interaction, etc…
-Make particle effects.
-Design your first level. Just blockout the level, don’t put a single material or assets in it. Use simple things like cubes, spheres, etc… Once you have all the level blocked out, and you can play it 100% of the way through with all puzzles and enemies, then you can either start making your own assets, or just use online asset packs, and make your level look nice.
-after this, do sound design. This includes music, and all the juicy feedback for the player.
-And after this, it’s pretty much just polishing and whatever else you wanted to put in the level. You of course can make as many levels as you want (Literally do whatever you want to do).
I hope this helps! And if you have any other questions, feel free to ask!