His medical background helped lend credibility to his work, especially Andromeda, Coma (which he directed) and The Terminal Man. Of course there's also the overriding elements of sci-fi, ranging from Jurassic to Westworld (which he also directed and is tentatively awaiting a remake). Corporate scandals were also a topic of interest in the early '90s with Rising Sun and Disclosure, and The 13th Warrior offered his own take on the Beowulf tale.
I remember his Prey, about nano-technology gone awry (but of course), making for a fun enough read and relatively ripe for a film adaptation (one that, as far as I know, has yet to be considered). Regardless, the man's works on-screen and off were entertaining and influential more often than not, and it's a pity to see him go.