Original credits go, of course, to Tim White's 'Lord of the Spiders'.

My above comment did not aim at removing all reference to Franck Sauer's Amiga image. No doubt it was the inspiration for Mouse's C64 image. It just seems appropriate to mention the original artist, Tim White, as well.
The image shown above IS Franck Sauer's Unreal title picture, after all.

Oops. I guess the sky can't be done with the C64's palette. Atari 800 or CPC?

After having looked at Mouse's other pictures, I think this one has probably been done on a Commodore Plus 4, too.