I know I just posted a Touhou-x-Undertale arrangement last week, but Eban's fusion of Cyber's World with Childlike Duo was too good to ignore.
I'll redeem the situation by expanding the subject of Touhou-style remixes, sometimes called "ZUNish" (or at least that's what I like to call them). Aside from examples of non-Touhou affiliated pieces being remixed into ZUNish, there's a surprising amount of remixes that spin a Touhou piece into the style of a different era of the series. I've shown examples of this before (notably from Paradise of Boundaries and Eban), but there are plenty more that are equally worth sharing.
DF will probably want to skip the second and third features, though.