A few things!! (Music nerdery ahead - fair warning to everyone else)

The biggest one is that both of them are using "ground bass" lines i.e. bass lines that repeat over and over and over again, but they also both (originally) contain "blue" notes, or notes that don't fit into standard western harmony as we know it, usually 7ths that are flatter than they should be.

In Crabbuckit, there's these sort of "cluster chord"-y piano shots that are pretty dissonant. It's a technique popularized by Thelonious Monk to try to imitate notes that can't be played on a piano. These same notes also appear on Harpsichords, or did.

When harpsichords were in fashion, the tuning system we use today wasn't around. In our tuning system, 5ths are "squeezed", so that we can play all 12 keys on one keyboard. the fifths were more "pure" in their tuning system - but that also meant that when you started to go into keys with more sharps or more flats in the key signature, the notes start to get more and more squirrelly.

Here's an example of a few different old school tunings. I know, I know, it's Pachabel's Canon, but the video illustrates what I'm talking about really well.

Hear some of the "weird", "out of tune" notes? especially as it starts to add more accidentals? This stuff happens especially in minor keys, and often composers would use those notes on purpose, just to twist the knife a little bit. So both pieces are using different techniques to attain those "blue" notes, just as blues guitarists do when they bend notes.

Here's more on Bach's tuning stuff. I could read this shit all day.