Each line costs you 10cents = 1 credit, so thats 50cents if you play 5 lines.
You cannot change the amount of credits per line. Its fixed.
The button panel lights up to tell you how many lines you're currently playing during the spin, thats all. They are supposed to light up together with the line tags. Mine are all lit if I play 5 lines.
Also, whats the chances of other MK2.5 games appearing, like "Clockwise" etc
These will all run on Mark 2.5 machine. We are not sure what eforest is though.