A quick update:
Still fits on a single floppy! Just. Although I could crunch the exe and get more I reckon. (Anyone recommend a good AGA executable cruncher?)
Some of the sound effects are in and working, sadly the music and sound effects option is working but not properly so I may have to do music OR sound effects. I hope not, more coding needed...
And more still to do, like fix level 10 so I can continue, the map is messed up there at the moment.