D7 Chex Quest on Scratch is a recreation of the game Chex Quest--released in 1997--which was in of itself a parody of the popular Quake game Doom--released 1993--
"The original game concept [for Chex Quest] was created by Dean Hyers and Mike Koenigs as a non-violent CD-ROM computer game to be released with 5.7 million boxes of Rice Chex, Wheat Chex, and Corn Chex cereals in order to cast Chex as a cereal that was exciting and fun for children..."
The games creator, @BobzGames, may have chose to recreate Chex Quest instead of Doom because of it's non-violent nature (appealing to Scratch TOS) and originality.