Sepulchritude is, of course, a solo fan album for Problem Sleuth, 12 tracks long, pure 8-bit goodness, from 2013. It may or may not have (unlisted) references to other music - could just as easily be a completely original album.

Curtis Lyon's discography spans 2012 to 2014 and has a great many smaller to larger releases; to the best of my knowledge, these are all completely unrelated to Homestuck or MSPA.