I was playing through this game normally, preparing for a couple IL runs, but i discovered this little skip that skips a couple seconds at the start of the boss.

What you need to do is run to the full right of the arena and stand there, you need to stomp on the first barrel. once the second barrel comes, jump so that you stomp it at the height of it's leap and hold the jump button.

This skips the other barrels that you need to stomp in order for King Barrel to land, as it is the bare minimum to start the cutscene.

Hope this gets used in runs soon!

We already have a skip for the first barrels. All you do is spawn in the second player, then jump on top of him/her to boost yourself up like the green button would. This makes King Barrel drop down right away. Look at WR run for reference.

Good find though, appreciate you posting.