Just wanted to chip in some low-end numbers for my laptop.
Athlon II P360 @2.3GHz
AMD Mobility Radeon HD 4250
8GB RAM
I'm running at 800x480, shaders set to medium, everything else set to minimum, and I'm getting 60 FPS with no bricks, 45-55 after loading something moderately big (ACM City, in this case).
So yes, some IGPs can sorta handle the shaders.