It's not just kanji, it's also the entire vocabulary being used.
For example, contrast a line taken from the Japanese declaration of war against United States and British Empire: "朕茲ニ米國及英國ニ對シテ戰ヲ宣ス", with its translation in modern Japanese (that I found on Japanese Wikipedia, so standard caveat applies): "私はここに米国と英国に対して戦争を行うことを宣言する". Notice the difference in vocabulary. And like I said, I could mechanically translate the original line into something actually resembling Classical Chinese: "朕茲對米國及英國宣戰", where as modern Japanese... not so much (in pseudo-Chinese form it would probably look like "私此処対米国及英国宣言戦争行事". Don't quote me on it though.).
This is because formal writing of that era was evolved from sōrōbun (候文, the original pseudo-Chinese, if you will), which looks like something like this: "新年之御慶目出度申納候" (Well, not exactly. What is printed out as computer-readable text is a lot more normalized than what was actually written out with a brush pen), which in turn was ultimately evolved from Classical Chinese.
To bring it back to pseudo-Chinese, since it's an Internet meme, there really isn't a canonical form. Its resemblence to Chinese is dependent on the writer's familiarity with Chinese and its vocabulary. Sometimes there is actual unadulterated colloquial modern Chinese embedded in it (thanks, momio and Azur Lane). Can't post any example though, because that will get me turbo-banned from this forum (thanks again, momio and Azur Lane).
Make no mistake, this does not mean that modern Japanese people can understand modern Chinese or vice versa with just some simple modification. The languages have drifted too much for that. Hell, it doesn't even mean that modern Japanese people can understand Classical Chinese without some serious annotations and explainations... then again, the same thing could be said of modern Chinese people as well.