How difficult/complex is the gameplay? How much of a time sink is it to get the most out of it in terms of building stuff?
Is it more akin to Minecraft/Terraria?
The day cycle is a period of 18 hours in game (or 13.5 minutes real time; one in-game hour is 45 seconds) from 6:00AM to 12:00AM (Midnight).
So to get through year 1, you need to spend 25 hours. And that doesn't account time when the clock stops (opening boxes, reading letters, cutscenes, ...).