Here's a simple 'alternate path' series.
1.) Play as different people (you're given the option previous to each action segment)
2.) Do things differently (i.e., alter who you save, who wins a battle, etc.)
3.) Alternate Doorways (you assume, in a Nintendo game, that there will only be ONE door per area? Heeee....)
4.) Event Mode (Remember? Events? Big, wild, out of control sequences?
...Speaking of the Boss Mode, it was always another of my wishes to let several players team up to fight overpowered boss characters... seems like I got my wish ^_^