You can kill hostages in counter strike and you will have - money at least it was like that in last version 1.3 of game that I played
But if seriously. Game that have lot of features ( This current is bad example ) gives you more things to do and not so monotone will live long. Swat, Raven shield etc etc are good examples from old school fps shooters
side note : It was actually hard enough to get such score in vanila
