I'm unable to summarise this properly — the "article text" you've provided is just PC Gamer's site navigation and membership boilerplate (menus, subscription prompts, category links); it doesn't contain any of the actual article content about the retiring Valve programmer or the game mode in question. I also don't have web access permitted in this session to fetch the real article myself.

Could you paste the actual body text of the article (the paragraphs describing what the programmer said), and I'll produce the summary in the requested format?