I played a lot Heretic I. Didn't knew they made a sequel tough.
Heretic II was fairly famous during 1999, however it never got along well with Heretic 1 or Hexen fans, mostly because it was a 3rd person game and not a 1st person one. However, other than that, Heretic II was a game of higher quality if compared with the rest Heretic/Hexen series.
If you wish to know how it looks like, here is a YouTube link: