For the record: Japanese and Chinese both make extensive use of logographic characters originating from China (these characters are called kanji in Japanese, hanzi in Chinese). There are some notable differences in meaning, but for the most part these characters are the same. However, Japanese has an entirely different grammatical structure from Chinese, so it uses those characters in very different ways. As a parallel, French and English both use the Roman alphabet but they are obviously different languages (French also has many more accented characters). And while Chinese uses the logographs exclusively, Japanese uses them together with syllabic characters known as kana (katakana and hiragana). Katakana is commonly used to spell out proper names and loanwords, and it is used for all the Pokémon names in the screenshot. These kana, although inspired by Chinese characters, simply do not exist in Chinese.
Also, there is no such thing as screenshots being written in Mandarin Chinese. The person who said that was just digging himself or herself into a deeper hole of ignorance. Mandarin is a dialect of Chinese, which means it's a different way of pronouncing the same written words. Think of it like a British accent vs. an American accent: the words are (mostly) spelled the same but the speech is different. Of course Chinese dialects are much further apart in pronunciation than a simple change of accent. Unlike Roman alphabets, the graphical characters don't give a lot guidance for pronunciation. So dialects are different enough to be considered a distinct language, often unintelligible to speakers of other dialects.
It is true that there are two major forms of written Chinese: Simplified and Traditional. The Simplified form (the standard of mainland China) was only introduced fairly recently by the communist People's Republic. So Japanese kanji mostly consists of Traditional characters, which are also used in Hong Kong and Taiwan.
Thanks for this detailed answer man. I learned much of this post! :)