I played Top Secret when I was in Jr. High School. It was a blast. One thing I do remember though was that friends and I figured out was that Top Secret was a lot more deadly than D&D was. One shot lucky head shot could take out your character permanently.
I'd eagerly join in a game of Star Frontiers, Marvel Super Heroes, or even Boot Hill.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.