As I've said before, Super Mario 3D World is a great multiplayer co-op game. It results in utter chaos and frustration as people yell at each other while laughing hysterically at all the mishaps. 

However, when trying to complete a challenging gauntlet such as Champion's Road, multiplayer takes on a different form. Instead of working against each other for fun, people suddenly become more cooperative. We need someone to survive this jump, so we don't haphazardly go for it until everyone is ready. We also nominate champions of certain sections - if someone is almost guaranteed to be able to clear a certain section because he's better at it, we all stand aside and let him do it solo.

By far, the most useful aspect of multiplayer for trying to clear gauntlet levels is that we have more than one life while attempting the level. Normally, Champion's Road doesn't offer any powerups or checkpoints; you have to do the whole thing in one try, start to finish, and you can only afford to take one damage the whole time. This obviously changes in multiplayer, as with enough lives, it becomes a common strategy to leave one person on a platform while all the "small" players jump off the cliff to respawn at full health.

Again, this is all a testament to how amazing the 3D World gameplay is in multiplayer format. It also highlights how well people can work together when they really want to achieve something.