tl;dr If you liked master of magic or age of wonders 1-2 then this is a
definite buy, if you didnt like those games then avoid for now
Alright my impressions after 8 hours would be this is the game I
wish Age of Wonders 3 had been but wasn't. It seems the developers looked closely at what made AoW 1 and 2 so fun and went with that. Its not a copy but its so close it feels like the true AoW3 I wish I had gotten instead of the souless game that turned out to be. They also seem to have looked closely at some of the funnest parts of the original Masters of Magic game and included those as well.
Im playing the first scenario in the campaign on standard difficulty with a Artificer and going in completely blind. Not sure if there are guides/recipes etc online yet but Im not looking anything up this first playthrough. That said its fairly intuitive, rune making is basically looking at color combinations on items and ingredients and combining them in different ways to see what you could get. Fairly simple and I had no problems figuring that out personally.
Spell research is fairly straight forward. Research what you have unlocked and new things get unlocked. Im not sure if its random each playthrough as to what spells unlock when as this is my first playthrough so we will see.
Units are actually really interesting and fun, you can mix and match whatever you want inside a stack (no moral malus for goblins hanging out with humans for example) and stacks are kept very small so you dont have big doom-stack battles which I prefer. Im up to 4 in a stack plus a hero but the undead mage guy can have 7 total in his stacks so not sure if that increases or undead just get larger stacks to start. Im 11 weeks in so not too far.
Art is beautiful and really pulls me into their world. The handcrafted world map is full of character and interest. These feel like HOMM maps from back in the day rather than the generic procedurally generated shit that always feels AI-art, passable but just not right. Unit art and effects are charming without being overcomplicated.
Music is ambient and inoffensive but also not very interesting or unique.
UI is lean and to the point but not so stark as to feel out of place in the fantasy world, Solasta Im glaring at you with this comment.
Challenge isnt too hard so far but I am just now getting into it with the undead mage faction and I lost a stack to destroy his invading stack. I was able to revive my hero afterwards so it wasnt a huge deal and he left me alone after that although again Im only 7+ hours in and cant speak much to challenge until Ive won/lost my first attempt.
Finally the randomized adventures are well written and simple. They make the world feel a bit more alive and fleshed out as they are handcrafted but spawn proceduraly. Not sure how well this will hold up in repeated playthroughs but the writing on the tin says there are a tonnage of them so hopefully they wont get repetitive fast. I do wish there was a separate mini-quest journal as it can get really confusing who needs to go where and some quests require you to return to x and unless you just memorize that fact you may never complete it later.
So these my first impressions for now. I would say Ive gotten my money's worth already as I will be definitely playing this past the 1 dollar/1 hour ratio I judge games on at the most basic level. Hope this helps some here make a decision one way or the other with a bit more information going in.