Looking good, particularly the in-game tune! A few suggestions though:
1. I think you should use the HAM version of the title screen, it looks so much better than that 32 colour version. No code would need to change except for making it 6 planes and setting the HAM bit. (Dynamic 32 colour palette would need more tricks obviously).
2. The hyphen character used in the credits font looks messy when used for underline. Can you use another character that has a continuous 8 pixel line nearer the top, or just change the hyphen if it's not used anywhere else? It'd look far more slick. (Like how NOMAD did in his AGA fixes).
3. Make the system-configuration file contain all black for the palette so you don't see the ugly Workbench screen in the background.
4. There's a few glitches here and there at the end of various parts where the screen flashes up whatever's left in memory.