In this horizontally-scrolling maze game, You the heroic knight must reach the top floor of Castle Cavelon, rescue a fair maiden and do battle with the Black Wizard! Armed with bow and arrow and a magic sword, you must avoid or kill the castle security guards while collecting the 8 pieces of the exit door that are scattered around the corridors, in order to proceed to the next floor.
It's not really clear from the store page but this is for the ZX Spectrum version, not the arcade version. The mapping is slightly odd on my computer as well - it's space bar to activate the Excalibur power, and when you run out of them it fires as well. It's nice to have this available on PC, but it is a shame it's not the better arcade version.