Playing this via the Amstrad core on MisterFPGA - excellent game but there are several uncomfortably long blackscreens between screens?
Viewing post in Bomb Jack Extra Sugar comments
That's when it's loading and/or saving to disk. I don't know if the Mister core provides direct file access as well as disk drive emulation, but if you can run it directly from a directory rather than as a disk image you might be able to get it to load a lot faster. I don't know anything about the Mister, but running from an M4 card into a real CPC, the loading times are almost zero, so maybe you can set up the Mister to behave similarly.