I agree with RavenMaster and sp3000. A sequel isn't necessary. An optimization patch is. With my GTX 480 (863/1725/1050) and dedicated GTX 260 CORE 216 55nm SC for PhysX (626/1350/1053), I still get slightly under 30 FPS at some points. If an enemy steps on screen, I automatically get 30-40 FPS. I run the game maxed out with AF and AA.
One interesting note about performance - the tech demo, in which I average 65 FPS, uses my GTX 260 sometimes up to 50% or more. The actual game doesn't use my GTX 260 very much... it's max usage is under 30%.