I've been playing Evil Genius lately. It's still quite good fun torturing your enemies in a mixing bowl, or slamming them between the bookcases to extract information. That and coming up with networks of traps to dispose of intruders to your lair.
Syphon Filter. Much more fun than MGS imo. Going back a little further, Scramble. Got a copy on GBA a few years ago and it is very moreish like many of the old arcade blasters.
But I am not sure what is counted as old...if that isn't old enough Gouls and Ghosts!
I did have a game on my Amstrad CPC which had an old scientist on a skateboard trying to get away from the left hand side of the screen...though I don't remember the name.