I think you're confusing games that are available on Steam with games that REQUIRE Steam.
It's sold exclusively on Steam, but, as far as I know, it doesn't actually use Steam for anything. So it COULD have a retail release.And what is the point of creating a list of UE3 games that don't require Steam?
Brizz, you're wrong. Saw can be bought on PC only through Steam. AFAIK there was no retail release on PC. Retail was done by Konami on X360/PS3.