You may want to see your doctor if you're getting a headache due to the flashing. But yes, having an option to turn it off or dim it would definitely help people who have epilepsy. The lightning is nothing new as the first Azkend has that as a power-up and it's never bothered me. If you think the lightning on Azkend 2 is bad then you haven't experienced pure unadulterated flashing and strobe effects in the form of Beat Hazard Ultra. That game is guaranteed to burn your retinas if you play it in the dark for a good hour or so. I can still see enough to make this post, though
I think it may have been because I was pretty tired/did not get enough sleep. For some reason, Beat Hazard does not have the same effect on me. I think it might be because the flashes don't usually fill up a huge chunk of the screen in quick succession like the coil lightning does in Azkend 2.