Patison has found an article about a mysterious PC game called “Murder City” in an old Polish gaming magazine. There’s not much info on the game, only two screens (probably renders) which show some futuristic buildings and a little description, which says: “Somewhere in future, in gigantic, dark, Megalopolis” and other PR text. But there is another interesting part, saying: “You can flight anywhere, in this huge, vector, cities of future” so it could have been a Descent-like game. The Polish publisher was going to be Techland, but as far as we know, this game was never released.
Update: the game was released under a different name – Crime Cities. It was pretty much Descent meets G-Police.
Thanks to Patison and Hyde_PL for the contributions!