Sorry guys, I fucked up in the stupidest way possible. Any avatars, attachments or media uploaded in the past month may be broken. The bulk of those are attachments.
Affected posts are by Brite / Dr. Minty Fresh / HeCooksPattiesAndSellsThe / Catalystl / ilikebreadtoomuch / Draco / minecraftstorymodefan / Extra Life / darkruler9229
Affected posts are in threads Quick Modding/Hacking Answers Thread / CS ~ Encore / game opens in 1080, occupies only the top left corner / Friday Night Funkin' / Bluebot Requisition - DEMO / Show us your desktop / Cave Story Season 2 / gacha cave story pics / Cave Story with XBRZ filter / Project Ampersand
Ok, so I'm a lot late to the topic, but I found out that if you change the date to, let's say, before December 31 2020, the website still runs. It didn't work on Chrome for me, but I tried Internet Explorer and it ran just fine.
Alright I'm waaaaay too late but after removing http://nisamerica.com/games/cave-story/ from unit_top.swf>scripts>DefineSprite (83)>Frame1>DoAction and putting the music files inside a folder named sound it restored the BGM button.
Using inspect network activity I also found out that the Story, Reviews, Characters, System and Media tabs have their own swf files.
Now I guess the website is preserved, click here to download it.