So I finished the alpha with my arcanist lich. Steam says 24 hours, which is a hell of a lot for an alpha so that's cool. General notes:
-Gets progressively buggier as you go through. At one point my save broke completely on whenever going to the adventure map and I had to reload a ways back to get it working again. But meh it's an alpha, it should be expected to be very buggy.
-Performance is also complete dogshit. I played most of Kingmaker on high settings and it ran fine. The alpha I played on low settings most of the time and got lots of stuttering and saving/loading took a long time. Again, alpha - I wouldn't expect the devs to do a major performance pass until much later.
-Some of the mythic abilities are ludicrously powerful. 4 extra spells per day from 3 separate levels? Permanent rage? Haste + blur whenever entering combat? Sounds like it might be too much but after playing I'm pretty ok with it because:
-Overall it's much more difficult than Kingmaker. I played on core rules (which is now a default difficulty setting) and found it solidly challenging. The fact that so many enemies are demons means lots of resistances + enemies do lots of status effects to you. Caster AI has also been boosted for some casters, hopefully it's still work in progress though because many casters you can still just select all > left click and kill very fast. Still, I'd say there aren't enough party vs party fights which are always the most fun in this type of game.
-Regill is by far the best companion. Awesome lines, great delivery by the voice actor, and it doesn't hurt that he does excellent damage after buying the extremely good gnome hammer sold by the quartermaster and taking the dex to damage mythic feat. Overall writing is pretty mediocre however, though it's obvious there's a bunch of placeholder stuff, especially for some of the companions (the game completely forgets about Woljif at a certain point and you just permanently lose him).
-Didn't have much opportunity to play around with the lich spells before the end of the alpha but Repurpose seems like a lot of fun. Do damage over time plus if the enemy dies while the spell is active it gets revived as an undead under your control. Went around with a personal undead fiend minotaur guardian for the last couple fights.
Overall it was a lot of fun, I'm pretty hyped.