I first saw this game on the Vectrex video games machine, it was a reproduction of an arcade game (the name of which escapes me) and was very good, both graphically and in game play.
The Commodore version of this game is also quite up to scratch. The game itself is played on a 3D grid similar to Tempest with nasties coming up the grid, or web, and either roaming around or blocking off chunks of the web so that your manoeuvreability is impaired.
You have a small zapper craft that can move up and down the 'in' axis of the web and from strand to strand across (a la Beamrider), you can shoot up and down, though you can't move where a strand has been blocked. Though a blockage an be cleared if early enough.
After a certain number of nasties have been cleared, you knock out the giant spider that appears and go onto the next web.
The webs are all different and a different style of play is needed for all of them - especially the upside-down ones!
Fast and furious, the blast-'em-up game of blast-'em-up games.