I think solo is enjoyable up to a point. Story and NPCs are basically non-existent. Basebuilding is a big part of the game, not because it is essential to survival, but because its fun and there isn't a lot else to do besides that and explore. You explore because exploration in the game is good, but also to open up new building options. But without others to appreciate the great things you can create, it can feel empty. While playing, I often find myself wishing my friends would have agreed to play this one with me. And as Arytoan points out, the qualit drops off. Or, at least, things start to feel a bit samey after awhile. Maybe the full release will be different, but after about 30 hours in and without others to amplify the fun that's there, I'm starting to lose interest. I'll probably get to about 50 hours.
Despite all that, I'd don't regret the time and money I spent. I just wish I had played it with others.
The story has been pure background journal text. Some of it is kind of interesting with snippets being found all over the points of interest that detail how the world was being ruined. A fair amount of those journals are written by the NPC's that are placed in the player base, so they get a little more character beyond the sparse dialogue. I'd guess this will remain a consistent aspect for the rest of the game's development, for better or worse.
I'm going to finish out the current content. The difficulty is getting decently hard at the level 25 cap but that also depends on how willing the player is to not abuse the AI. Most of my damage comes from a ranged bow but the AI has a lot of trouble with the player being on higher ledges. A lot of enemies have no ranged option so they just stand there and get pelted to death if I want to jump up somewhere. There are highly aggressive green glowing scavenger enemies later on that I've cheesed a great many times with either verticality or a talent that constantly stuns enemies with special shroud arrows. Just a lot of balance issues all around to clean up.
I've really enjoyed it though. A solid foundation and a 9/10 for me personally. Most of what has me enamored with it:
-The art style just does it for me. The clashing of forest with the shroud. The buildings look gorgeous. Glowing lights in the night. Just a good atmosphere all around.
-Night and day system actually has meaning. Often when exploring the day falls to night and I need to use light from a torch or off of a sword. It enhances the danger considerably.
-Digging has consistently been rewarding. Last night I'm in a desert area. I see some odd ruins with nothing there. Dig down into the sands and find a small dungeon beneath. Neat stuff.
-The grind for materials isn't overwhelming. I played Valheim a few months ago and there is nothing like the Iron grind there. Getting any material here is far easier, save for maybe Flax which can be grown at the base. The timers for making materials on crafting stations are also not overly long either.
-The enshrouded timer actually works well. It can generate some good tension when I'm delving far into an unknown area and I choose to press on without knowing whether I'm going to be able to get out of it in time.
-Areas have a lot of mini-puzzles that can keep environmental traversal interesting. Double jump is a little too easy to get and makes light of some of this but not all of it.
-Items don't have weight so the player is only limited by the amount of slots, which are upgraded through bags. Greatly alleviates a lot of frustration with needing to head back home too early because of carry weight issues. Which again, leads to enhanced exploration through the day/night cycle.
-Lastly, the building system is fantastic. It is possible to make very elaborate bases or even just dig into the ground and make a hobbit hole if you wanted to. Even possible to restore a ruined town found in the game. No physics/structural element though, so things can just float in mid-air.
But as I've said before, I've got several dozen things I'd change or add. The lack of weather is my biggest gripe at this point. There is no comparable moment to Valheim where the storm rolled in with the rain pattering the roof as I'm cozy by the fire making sausages. Maybe I'll end up making a list from big to small things I'd like to see for a roadmap or patch notes.
