Hard to figure out, and kind of slow once you do figure it out, but I still had a little fun. Judging by the other reviews, it needs a win condition. Perhaps one last, game winning upgrade that makes the death ray powerful enough to blow up the earth would do.
A few playing tips: When a valve shifts, there will be a hiss, and big white lines will be emitted from the valve that is shifting. The thing that directly determines how much the generator or capacitor is being cooled is apparently neither the temperature of a cooling room nor the position of its valve, but how many dots are flowing through a light blue pipe connected to the room. It is possible to save the death ray after the capacitor blows up, but you must not waste any time. After turning the cooling rooms, immediately turn the control room valve all the way and fire when it says fire. If the capacitor blows too soon, it's probably overcharged in which case your only possible hope is for the generator to blow up before the ray gets too hot and THEN to repair the capacitor and then quickly repair the generator.