The worst sequel to a game?

[The Ghost of RubangB]

Bruno Muñoz B said:
Chrono Cross.

I was going to say Super Mario Bros. 2.  The real one in Japan, ya know, "The Lost Levels."  It's basically a nightmare mode mod for the original, but was actually called Super Mario Bros. 2.  I think the only things they added were poison mushrooms, warp pipes that go backwards, and wind.

But then I read this post.  Chrono Cross.  Definitely.