Thought I'd jump on here and share some of my impressions with everyone. What I've seen so far was exactly what I've been looking for in games over the past few years. It's evident that a lot of hard work is going into the development of this game and that GPG is proud of what they've developed. They should be proud, because this is a refreshing game in what has been a sea of mediocrity.
A few things to keep in mind: It was a short 10-15 minute demo and you started out at level 15 with some serious cash and AI opponents. Oh and it was running on a beast of a machine, so it ran smooth.
The graphics are exactly where they need to be. Its clean, smooth, and beautiful. There is a lot of eye candy, but it isn't overdone. The game is great to look at, but that really comes across as just polish on the excellent game play that was evident. The screenshots hold true to the look of the game. Now we just have to wait and see how it holds up on various hardware configurations in beta.
The game play is simple on the surface, but it has just the right amount of depth. The skill tree concept works well here and provides ways to build diversity into the demigods. Each demigod has a specific role and that is evident in the game play. The maps, well map, was a lot of eye candy, but very simple. I believe it was built for 3v3 and it was just right for that because if you started from level 1, you really wouldn't want it to be much larger or complex.
I'd comment on sound, but I honestly don't know because it was incredibly loud in the exhibition hall.
From what I could get out of the individual showing me the game, it won't launch with too many maps and demigods which some may find annoying. I haven't had enough time with the game to really have an opinion because balancing the demigods that they do have will probably be a bitch, but at least GPG is putting some serious time into a beta to work that out! Maps will come with time, and who knows, maybe they'll release their platform tool for building maps... 
The game isn't a new concept, but there isn't anything wrong with that. It's a concept that needed to be professionally done by a game studio and GPG has done just that. The development looks to be coming along nicely and they haven't overdone themselves. Clear goals seem to be set and they are sticking to it.
I know this reads like a bunch of disjointed thoughts, but I thought it would be best to get those thoughts out there for people who couldn't attend PAX (which is an amazing experience). I did pre-order the game because I was impressed by the game and its creators and feel that I could contribute constructive criticism that they are looking for!
This game has a ton of potential and it deserves attention by game enthusiasts everywhere. If you want to help contribute and really help shape this game, pre-order it, get in the beta and start generating the feedback that they need because it benefits all parties involved.
