I'm not entirely sure as I haven't read it specifically. But generally, a light novel about slime recreation might be about the creation or re - creation of slimes. It could involve things like how slimes are formed, their characteristics, and perhaps some kind of adventure or story centered around the slime - making process.
Well, one obvious difference is the medium. Manga is visual, so you can directly see the slime's appearance, the expressions of characters, and the action scenes. For example, in a slime battle scene, the manga can show the slime's movements vividly. However, a light novel uses words to describe all these. It might describe the slime as a gooey, translucent blob that pulsates with a strange energy.
Well, without more context, it's difficult to say exactly. 'Slime' in light novels often refers to a type of creature, which can have various forms and abilities. The '300' might be a volume number, a chapter number, or something else entirely. It could be a story where the slime is the protagonist and there are 300 important elements in the plot, like 300 quests it has to complete or 300 different types of magic it encounters.