Wasn't really happy with this last one liminances.
This Ground stages have 3Parallax scrolling that like this would 'scroll looking' better:

One more stage colours/luminances it's done:

An A8 vs C64 pictures to 'start with':


All the other screens of this 'type of' stages screens can be found here:
http://www.atariage.com/forums/topic/177261-sub-hunter-on-c64-now-ported-to-cpc-when-a8-version/page__st__100


Greets.
José Pereira.

Lots of shapes just to show the 'PRIOR0' to get any colours/almost all luminances possible on Enemys.
Here there are by now 29colours with 6Enemys but ther's screens with a maximum of 8Enemys that will get something like 33colours maximum!