I just finished playing a three hours session with the Demo.
The first thing that really surprised me was the performance. At first I was like "ok, well, let's try a couple of settings at Medium first and set the res to 1024x768 because it's new and it might require a lot from my ages-old archaic machine". Well, with those "medium" settings I thought the graphics were decent, but I realized soon enough that I was running at a constant 30 or 40 fps without a single drop.
So I told myself "whoa, well ok let's try everything at highest it can be, let's add soft particles and the like, and let's increase the resolution to 1280x960, and let's add 16x A-F and 4x A-A". Well, yes, the performance dropped *some*, but that's the point, it never dropped "a lot", I STILL get 30 to 40 fps in most areas, with a FEW drops below the 25's here and there, although my system, except for the GPU, is quite old (at least on a gaming platform point of view). And at the highest settings I can safely say that it is the most beautiful OpenGL graphics I've ever seen. But despite being nice OGL graphics it certainly isn't as beautiful as current or future D3D9 games.
I like the weapons, the music (especially the music). It has an arcade-like feeling, mixed with some strategy. And, wow, the Bots guys, the BOTS are nice ! It took years and years but we finally get to see some very nicely done Bots right there. They can even complete objectives PROPERLY, how nice is that ? I mean they even WAIT for you and ASK you "need a ride ?" when they spot you (if they're in a vehicle). The Bots can PILOT aircrafts well, and the movements aren't just sudden turns, it's smooth curves in the air doing some cool maneuvers. I remember reading an interview with the guy who made the A.I Bots, that guy is ALONE, so he's most definitely a pro, my congrats goes to that guy for making the game cool even off-line.
It took me some time to get used to the weapons though, and trying to figure out what weapon does what and what were the proper counters to specific situations. Same thing goes with the structures that I THOUGHT I had to build when I saw their white wire-frame floating on the ground. At first I was like "ok hmmm ... what is this ?", "how do I build it ... and do I even have to ?", and then I figured out that stuff along with some other things (like how to use the Strogg jet-pack, or how one could call a vehicle and it'd drop from the sky like in Battlefield 2, although in a more "advanced" way).
So far I think that game has lots of potential, it's making me think I'm playing something like UT2004 with Stroggs and on Earth, literally (with better graphics too). I just wish that the physics weren't that ... hmmm, how can I say, "blocky" ? It just doesn't feel as sophisticated as Half-Life 2's Source physics (I think nothing does so far and since it was released). But, overall, it's a very solid game and is probably an infinite times better than Doom 3. Yup, I think id Software is back on track (I always thought they made nothing good since the original Quake, and perhaps Quake II).