Everyone knows that the original Kong, at a mere 25ft, wouldnt stand a chance against Godzilla. So in King Kong vs. Godzilla he was scaled up to Godzillas size. However, that wasnt the only power boost he got. Suddenly Kong can now generate strength from electricity. This ability of his is only slightly hinted at before the big reveal, and still it comes off as completely random. Kong is a giant ape; how does electricity make him stronger? At most it should be harmless. Now he can not only absorb it, but even shoot it out of his finger tips! Even worse is that Godzilla, who had previously been established as being impervious to electricity, is now weak against it. It makes no sense, but it is obvious that these elements were added to the script to level the playing field between the two. There is no point in analysing it any further; you just have to go with it.
