I think "Solaris" (Sinclair User cover game by Theo Develegas, 1990) is a
rip-off of "Speedzone" (Mastertronic, 1988).
You have to play for a few minutes before you notice this, because Solaris
has a prettier intro sequence and additional features like AY music, but
soon you begin to recognise the alien sprites and their movement patterns.
Not just Harry Price, eh?
Re: Another rip-off?
Might be worth checking this list: