Install
Install went smooth, I did have an error that required Impulse to close, but Demigod installed just fine.
Performance
Using Fraps my fps was almost always at 30, it never went below this even with lots of action on screen. I had all game settings set to high. My resolution is set at 1680x1050 with 32bit color. I had Vertical sync set on and AA was off. I had zero crashes and zero lockups
Some noted things, maybe by design at this stage.
There is no camera movement other then zoom.
Some of the UI buttons turn into a red box when used.
I can't scroll using the mouse.
Rook is a powerhouse.
My rig
AMD Phenom(tm) 9950 Quad-Core Processor (4 CPUs), ~2.6GHz
4094MB RAM Corsair Dominator DDR 2 1066 timings 5,5,5,15
MSI K9A2 Platinum V1
ATI Radeon HD 4850 512MB (using CAT 8.7 drivers)
SyncMaster 2253BW/2253LW,SyncMaster Magic CX2253BW(Digital) 22"
Windows Vista™ Ultimate (6.0, Build 6001) Service Pack 1 (6001.vistasp1_gdr.080425-1930) 64bit
Overall the game is a blast. I cannot wait tell it's goes retail. 
