Just remembered It Came From The Desert, although I had it on the Amiga (which was the much better version) it was also released for Dos.
An early freeroaming game mixed with B Movie themes, it had loads going for it. Incorporating many different styles (shooting, driving, exploration, mystery, flying, stealth...) along with massive ants and a hot nurse. What's not to like?
Highly recommend the Amiga version though as it looks so much nicer.