Wreckers:

Developed by John Heap and Denton Designs, this title was intended for 
the ZX Spectrum 128K, and was to be published by Audiogenic Software Ltd.  
Although it received high previews and a 93% review score from CRASH 
magazine in 1991, the game was never released commercially.

The cancellation is attributed to the decline of the ZX Spectrum market 
and potential issues with the conversion quality, though the exact 
reasons remain somewhat mysterious.