Changed the flies so they use just two 8x8 sprites with different palettes.
The player mettaur has 12 sprites (yikes!) arranged so that there's no need to overlay them. Maybe could try and figure out a way to shave off a few sprites.
That's already 4 sprites for a single scanline, so it limits the enemies to 3 or less, cause you need to be able to shoot at least one bullet.
This is really hard......