So making some good progress now

have added

• better enemy movement
• changed lighting - enemies now have a red light and play white and toned down the environmental lighting / added fog
• added destroy in enemy script on contact with player

to do

• start screen
• improve collisions if possible - its better but could be better
• enemies can sometimes go through walls for some reason even they have rigid bodies on both
• end game when all enemies 'killed'