The games on the CD are:
Star Trek Deep Space 9: The Fallen
PC Gamer Presents: They Hunger 2 (Half-Life mod)
Star Trek: Armada
Weapons Factory Arena (Quake 3 mod)
Red Faction Movie (trailer)
Pool of Radiance Movie (trailer)
I got this from the magazine (I'm not sure if the actual CD made it on the journey of our recent move). No Mechwarrior on this CD. There are illustrations for all of these demos and none of them match your description. I'll look at other issues around this date and get back with you if I find anything...