Originally posted by Discrate
Everyone of Valves games have a different source engine version. Each version bringing graphics improvements or something else new.
Oh, yes, that's true. But the basis is the same for all. Graphics didn't changed much, it happens that HL2 didn't use its full potential. THere were a few graphics improvements and specially AI Director.
Originally posted by foaly
the steam servers where really slow
They were overloaded, and only few non-Valve servers. Very soon (maybe today) everything will be more stable.