My first impressions are... it's rough. The combat is sort of a hot mess right now, and not just due to my own inexperience with the mechanics at play. It's too fast at its current speed (and I shouldn't have to turn on "slow mode" to keep track of what's going on) and doesn't really give feedback. Maybe if there was some way to make the characters more distinct? It's sort of hard to give feedback on a deeper mechanical level when I can barely understand what's going on. (also it's sort of hard to progress in this beta when my party keeps on dying to those lions )
Those issues aside, the game has the look and sound of an Infinity Engine game down and the usual quality of writing one can expect from Obsidian (i.e. good), and I appreciate the 2D Backgrounds/3D model thing it has going on, because it makes it look like Temple of Elemental Evil which I am fully in favor of.
It's very much an actual beta, that's for sure. I'll keep plugging at it until I can finish it at least once, though hopefully they'll fix some of the more critical bugs and issues quickly.