I just got through playing a few of the new demos, and I'm extremely impressed.
One: Wow. I had no idea a game that looks and plays so fluid could be made on the N-Gage. The detail is just amazing and the gameplay is really easy to get in to. The demo I played said it only had 30% of the attacks usable, but the game was still very playable. The motion capture is top notch, and the Create A Character is actually pretty fun. Aside from the gorgeous graphics and solid gameplay, I was most impressed with the framerate. In the demo I played, the framerate was constant without any hint of slowdown. That has been my big problem with several other N-Gage games, like Morrowind. There's no doubt in my mind that this is a game I must pick up.
System Rush: Like what many sites have already said, this game feels like a mixture of Tron and F-Zero. The sense of speed is pretty good, but I had a little trouble keeping my vehicle from going all over the place. This may be caused by my suckiness as a gamer, but I thought the controls could be a bit tighter. The demo I played wasn't very long, but the game seems pretty decent.
Mile High Pinball: I can't say enough about this game. It is just fantastic. Not since Alien Crush have I had this much fun with a pinball video game. The object of the game is to move the pinball up through levels by completing various objectives, like breaking a collection of bricks that is blocking your path. There are some pretty cool powerups that you can get, like a feather power up that makes your ball fall slower, or a balloon power up that makes your ball rise into the air. It all comes together to make a very, very solid pinball game. This is another game that I will definitely be picking up.
Man, it really is a shame the N-Gage is being discontinued. There are several awesome games coming out for the system. Only now, is it truly being able to show what it can do. Sigh.