This is a really good game, I got pretty addicted to it (though I'm definitely a fan of the genre). I really like the vibe and the direction the devs are going. There are a few "early" elements, but I hope enough people get the game to give the devs the $ they'll probably need to take it over the finish line.
Environment is awesome - one of the most "lush" and varied games I've played - meaning, none of the biomes feel sparse, they feel very, very real, at least in terms of "real" for the games world (which is great as well, in terms of it's art style). Exploration is a blast. When I started finding new biomes I was really happy, and I don't think many of them are featured in the videos and some of them are breathtaking.
Crafting is amazing, though you pretty much have to depend on the wiki right now for recipes, unless you are willing to really experiment. There's no tutorial (yet? maybe there never will be, not sure). All of the recipes make sense, but for whatever reason I couldn't figure many of them out on my own - there's a lot of possible combinations. My only gripe right now with crafting is that it is "automatic", meaning, whatever ingredients you are experimenting with will become SOMETHING if it could be a combination, so you sometimes don't end up with what you want. In other words, if you are trying to create a crafting table which needs vines, branches and chopped wood, you might end up with a "vine club" if you don't have exactly the right amount of the various ingredients, and then you've wasted a vine and branch (at least until you DO get the table done, and then you can de-construct the club). Also, sometimes you've got stuff lying on the ground nearby that gets mixed into your attempts. The best "lore-friendly" suggestion I have is after you've made something once, maybe your character thinks "I already have an X" and you get a chance to proceed or not create the thing (wow I went into a ton of detail on that....)
Progression feels really good right now, going from crude stuff into bronze is fun.
Base building or just choosing a good base (like in a series of caves or something) is pretty good - I prefer caves or other already-existing structures since building an actual base is a little pointless right now (at least from what I've played) and slightly tedious.
Haven't messed with alchemy yet but I suspect it's fun.
Stuff that is kinda meh right now:
The interface/control feels funky in places and needs some work (if the devs read this, I posted one suggestion already on the forum [user 503geek] and probably will post a couple more)
The AI, particularly pathing, is not good right now, but I suspect this will be fixed. So, combat is not really much of the game yet. Getting prowled by or ambushed by a tiger IS exciting though, even in it's current state. And I did get killed once, so I guess it's not THAT bad ;)
No NPCs, also something that will probably be added.
No story/quests, also will probably be added.
In summary, I think this is a great game, I definitely hope people will buy it so the community grows and the devs can have more resources. After the recent announcement about how they had to reduce the size of the dev team, rather than thinking "uh oh, this game is sinking." I bought it. So hopefully more will do the same, because I do trust them when they say that they're going to finish it. Frankly I've already gotten my monies worth if you use the $1/hr valuation. Last thing: I think multiplayer is going to be really, really fun when it comes out.