I give you Crysis 2 in 320*200 (scaled up 2x afterwards)
After this I set out to make "play like it's 99" mode.
So this is not actually low, but the textures are at
1/16 (!) resolution (of default at low). Also anisotropy, who needs it. Same goes with AA. Not hardcore enough. Shadow jittering lol. nope.
Actually Crysis 2 is the most impressive game at low. Incredibly smooth framerate on old hardware, while retaining stuff like dynamic lighting (obviously), SSAO, per-object-motionblur (!), DOF, postprocessing AA, Anisotropic 8x, dynamic sun shafts
but anyway. 1999. here it is. Note how the street texture in the first picture would still be acceptable for most current productions (with filtering of course), while being at 1/16th resolution.
EDIT: forgot that only 2 screens allowed, deleted some of these.