Horsburgh: I’m very happy to get this milestone…
It sounds like you’re referring to a statement by someone named Horsburgh about reaching a milestone—“300 worlds.” Could you clarify what “300 worlds” refers to? For example:

Is this related to a game (like No Man’s Sky or Minecraft)?
Is it part of a book, writing project, or metaverse/worldbuilding challenge?
Or maybe a sci-fi milestone, artwork series, or something else?
Once I understand the context, I can help you craft a proper message, summary, or interpretation.