I think the game disc you're referring to is "GCW Games for DOS", and the one with the vegetable gun is probably "Pickle Wars", the one with the robots is "Megatron", the disc contains, JJR 1, Scorched Earth, Jetpack, and The Adventures of Maddog Williams, the only the comes to mind on the insects in the desert maze is one of the Skunny series except for the maze part. The disc contains, Nightmare 3D, The Last Half of Darkness Part 1 (:akimbo:
), Doom, Cyberdogs, Wolfenstein, Stalker, War Wizard, Commander Keen 1, 4, And Dreams, to name a few. (big disc)