Online multiplayer couldn't do something like this.
I had people over and load NSMBWii.
They were screaming and laughing the entire time while the adults asked me why the kids are screaming. I said it was designed like that.
At one point where they got to the boss, everyone else died except the 5 yrs old nephew. Everyone cheering him on and he actually managed to defeat it. He was jumping around with a huge smile on his face.