I simply cannot force myself to try this anymore. This is a neat concept, but the implementation is infuriating...
I figured out the whole puzzle I am fairly sure. I know how to kill the boss, I get multiple hits in every attempt before the power goes out again, but nothing I do seems to get me there fast enough to kill him in time. I don't know exactly how many times I have attempted this now, but when I started to get angry I counted 10 before I gave up, because I hate leaving things unfinished and I am at the boss...
I don't know if the timer is a set number, a changing number based on how far you get, or if it's a random variable and I am just getting extremely unlucky, but this is much more stress than it's worth. If I am missing something, please tell me, but this was not at all enjoyable.
Great in every other way though.
Edit: After a friendly spoiler I was able to get it beaten. Still kind of stressful, but it turns out it was kind of my fault xD Slight spoiler