In the lobby, load up the Arcade menu with
or walk with your chibi character towards the right side of the platform, northeast from where you start.
Walk up to the guy with the purple hat in front of the brick tower in the middle of white clouds and click
. Then, select the first option "Begin Arcade" and hit
.
Select your three characters (any of them work fine) and pick the second arcade course "Extreme Gravity Spaceship Course". You'll have to win five battles, each one a tad harder than the previous and quite a bit harder than the Snake Way Sensei course, but you should be fine.
Just spam
+
to make sure they don't attack back. As soon as they do, switch characters by holding
to preserve your health.
The achievement will be yours once you win the fifth and last match.