Yeah I noticed the site is down as well just a bit ago. Could be a server overload or (and hoping not) a hacker of the evil kind has taken the site. If you still need an asset for your game you should be able to still get some off of GameDeveloperStudio's Itch.io page. I grabbed an asset I needed for about $5, I didn't check but I would assume there are some free ones as well. Here is a link so those that still need an asset won't be held up by this 404. and BEST OF LUCK TO ALL! https://gamedeveloperstudio.itch.io