Day and night have their own cycle, like Minecraft. Night is more dangerous and you can retreat to a house / bed to sleep it away. It's also the best way to pass time - there are some things, like smelting, that take time but are accelerated by sleeping through the time.
The combat is decent but this could also use some work, to be honest. There are six or seven different weapon types and, even with a few dozen hours under my belt, I am not sure what the benefit of each might be. They do different damage types (slashing, piercing, bludgeoning) but skill in each one is hard to build up. Bows are the only one so far that can do things like frost, poison, fire damage and they are largely OP. I expect this area to get attention and to become better over time.
"Saving" happens automatically and also like Minecraft. You cannot save your character and then reload if you die, and when you die your hard-earned stuff drops at a gravestone you have to get back to. Many people are making comparisons to the original EverQuest for its "corpse runs" and this comparison is apt. That said, dying comes through lack of preparation and skill and can be avoided in most cases.
The biggest grind comes if you want to get fancy and create elaborate houses, castles, villages, etc. These require a lot of resources. Otherwise it's not too bad, and there are ways to speed things up - teleportation, boats, carts. I expect that these options will increase over time as they add more things - maybe animals or something.
The game could definitely use some work. Dedicated servers broke for me (and lots of other folks) after the last patch, so they have their work cut out for them to get some of the basics down - but it has relatively few bugs otherwise. There is a wealth of content that will likely be available after 2+ years and that may be the time to jump in. If you have doubts, I would skip it for now and get it later. It might cost more later, however.