For all who are wondering about the Dan Hibiki medal:

To unlock it, you need to reach the final boss without using any secret exits, or cheats. I'm not sure if the yellow, green, red, or blue switches are allowed, but I reached the final boss without them just to be safe. You'll know you've done it right when you reach the maze section in Castle Mario and you see that the fireballs are green.

EDIT in response to Lambtaco's reply:
I see. Also, good thing I trusted my gut by avoiding the switches!

THIS IS SO GOOD MY JOYCONS STARTED DRIFTING🔥🔥🔥

I wish Rolling Sky used this for Beach Harbour, I love how ripply this is :)

This reminds me of Gummy Bear & Om Nom😭😭😭