Thanks for porting!!
This looks like a variation of Hyper Active, which Special FX did for the spectrum and was released on a Sinclair User covertape
Screenhots:
http://www.worldofspectrum.org/infos...cgi?id=0002413
The gameplay is quite similar, as is the loading screen artwork.
Hope you dont mind being asked, but what inspired you to convert this cool but obscure coverdisk game?