Yesterday, Undertale creator Toby Fox took to Twitter to tease a mysterious, new project. A series of cryptic messages indicated that something "very, very interesting" would be revealed in 24 hours. The big reveal came today in the form of a website called Delta Rune which has a download link to something labeled "Survey Program." As it turns out, the true nature of the announcement is much more complicated than a simple survey.
Once you've downloaded and installed, the program is revealed to be a brand new game, or at least a demo version of one. Delta Rune, which happens to be an anagram of Undertale, is a new adventure. But it should feel quite familiar to those who played Undertale, and there are some obvious connections between the two games. Just how does it all fit together? We won't spoil the details, so you'll have to download it (free) and try for yourself.
Source: Delta Rune