I played the ZX Spectrum version a bit.
Nice game! You use the limited possibilities of the hardware really well.
The game is very easy to get started but becomes really difficult fast. So far I did not manage to come deeper then level 5.
Could you tell me please if the statues and fountains you enconter from time to time have any meaning or are purely decorative?
P.S.: The link to the BASIC compiler you've used is broken. I'd love to have a look into this as well.