The Game in short:
Old school "crpg" gameplay & aesthetics.
Fantastic writing and a story you _will_ get drawn into (eventually - see extended comments below).
Squad-based tactical combat and customizable characters.
Enjoyable loot hoarding.
Insanely good value (at time of writing I have 63 hours on one play through - not bad for $10).
As others have said, this game is graphically moribund. If you've played other Spiderweb games you already know this (and you are already familiar with most of the sprites and textures). **However** the graphics really don't matter; after a while the graphics will look better and better because this game _will_ engage your imagination as you personally construct the world Avadon presents (this is probably an effect of all the reading you will do - think of how personal and vivid the reality of your favorite book was at the time of reading).
The writing is great - I haven't been a reader of high-fantasy fiction in decades, but I have still thoroughly enjoyed the story so far. I believe this is because in this game, your decisions, well, erm... might matter? This is a key point: while other games claim to have 'decisions that matter' simply because player-decisions have some visible and immediate affect on the world, in Avadon 2 you are often forced into difficult decisions and then given no clear indication of what effect (if any) they had. This isn't to say that nothing happens- NPC's will mention your prior decisions and give you the impression that certain things may yet come to pass because of them, but you are left wondering until such outcomes do (or don't) occurr.
With all the above said, I will admit that it took a while for me to get drawn into the game world. In the beginning, it appeared simple and I took it at face value - I was probably 30 hours in before I began to realize that the world of Avadon is truly constructed of shades-of-grey (and perhaps, like a good book, is constructed to allow the viewer/gamer to reflect upon their own world, should they so choose). For anyone not interested in contemplating the morally-ambiguous complexity of safety-vs-freedom and power-vs-control the story may remain simple.
Combat is tactical and (mostly) squad-based. You will usually control 3 characters in a turn-based battle system that can have difficulty adjusted to suit your individual taste (I kept things at 'normal' and found combat satisfying, if not overly difficult).
The game world is a scattering of regions, each containing 5-8 maps or so. Regions are all connected to Avadon, which serves as the primary hub and base for missions. Side-quests galore exist (I've been trying to do them all, which is probably how my hour count got so high).
Prior experience with Avadon (or other Spiderweb games) is totally unnecessary. I own Avadon 1, but have never played it. My only other Spiderweb experience came from playing through the majority of Avernum: Escape from the Pit on an iPad (though I never did finish that one).
My only real complaint about Avadon 2 is the lack of UI-control customization. I would love nothing more than to be able to toggle Windows open and shut with the same key. Additionally, I'd love to be able to stop accidental touch-pad clicks from closing important dialogue windows (I've several times now missed out on reading some vital piece of conversation because I accidentally shut the conversation window and the game offers no way to undo such actions).
In summary - the game is fun, cheap, and surprisingly engaging on various cognitive levels. I recommend this to anyone, but particularly to smart 30-something gamer dads like myself.