Good shooter for an older PC?

From old fashion games i would like even they would bring alive now:
Iron Grip: Warlord
Medal of Honor series like "Allied assault" and also it's expansions like Spearhead or Breakthrough; Pacific; i think Allied assault multiplayer it still running with some cool modded servers
A little horror and exploration and puzzle game like Penumbra series Overture, Black Plague, Requiem.
Of course how without cheeki breeki S.T.A.L.K.E.R. series.
Also the Deus Ex: Human Revolution.