All I remember is it was set in space and was based around humans and aliens dueling in an arena. I think it was 80s possibly early 90s and I'm sure one of the monsters looked a little like a giant cricket, and its weakness was its stomach, and another alien had cybernetic attachements please please please does anyone remember what it was called

I wonder if it might be the aptly-named Arena (http://www.imdb.com/title/tt0101366/) from 1989, featuring a couple of familiar genre faces in the form of Claudia Christian and Marc Alaimo.