20 Styles of Hardcore Techno in 7 minutes (From the Mainstream to the Obscure)

Did you know The Hardcore Overdogs do video features, too?
20 hardcore styles, genres and subgenres in 7 minutes, with audio examples and short explanations.
Not all of these are "true" genres; some sub-styles, and general concepts that some producers followed, have been included too, and some of these terms are more like "placeholders" than actual, widely used genre names.
But these sounds definitely existed and are worth being mentioned.

The following styles are included:

Speedcore
Acidcore
Doomcore
Oldschool
Extreme Hardcore (also known as "Terror")

Experimental Hardcore (Stuff like Fischkopf, Praxis...)
Breakcore
Hardcore out of France (not Frenchcore)
Tracker Hardcore (i.e. done on tracker daw software)
Industrial Hardcore

Ravecore (sometimes called Trancecore)
Broken futuristic hardcore
Chipcore
Early Speedcore
Early Hardcore (gabber type stuff)

Hard Acid
Technoid Hardcore
Doomtechno
Slowcore
Dark and Fast (Dark hardcore tracks that are "too fast" for normal Doomcore)