Why Super Mario Bros. 3 was the last great Mario game.

[JUG]

The Ghost of RubangB said:
All the hardest games in the world are 2-D, from Battletoads to Ikaruga.  

What about F-zero GX? I played that for the first time a few months back, and I don't know about you, but I think it was pretty hard. I played Metroid Prime 2 recently too and there were parts of that game that were reasonably challenging on the basic difficulty setting.