For a period of about four hours last night (from 1:30 BST) the Game Maker Community was unavailable. Wade McGillis also reported that the main YoYoGames.com website was down.
This morning both are back online but it appears that the site is being restored from a backup – a process which has not yet been completed as files including game screenshots and game downloads on YoYoGames.com are not present.
The last time the site appeared like this it was explained as routine site maintenance conflicting with a firewall.