About the penalty kick thing and hockey's idea...I'm not sure if you could keep the game going unless they changed it. Add more Substitutions, shorten the field, etc. Because you also don't want it to come down to some sloppy tiredness that allows a goal to go in in a knockout round/final. Hockey's different with a much shorter ice, players constantly going in and out getting rest and water, and multiple intermissions and timeouts. Like the 1994 final or 1999 women's final both in the Rose Bowl both went to PK's. In the dead of summer when it was probably 100 degrees on the field, I don't know if you keep going. Plus you have to admit, the nerves are always high during PK's. I kind of like them.