why is it in Japanese stuff some text is still in English
There are several reasons why Japanese stuff sometimes contains English text. The first is due to loanwords [1]. During the Meiji Restoration, Japan standardized its language, and decided to borrow words from other languages rather than creating new ones, mainly from English [1, 3]. These words are generally written in katakana, which is a type of alphabet mainly used for foreign language loanwords [2]. Besides loanwords, some words are also used because they sound cool or are a way to make a statement [1, 2]. It is also common to see English used decoratively on signs and posters, or as gibberish text just for aesthetics [3].
The reason English text can be found in otherwise entirely Japanese productions is that English is fairly common in Japan. [2] People will use English decoratively, like on signs and posters where there's just a random paragraph of gibberish English text. [3] Often, people will be more playful with a language they don't really know. [3]