If you get far enough in Ninja Gaiden, you'll get to this fun thing

Which requires you to jump down, catch the left wall right before you plummet to your death, and then hop onto the platform below.

Which is a lot harder than I made it sound.

But!

If, after you press Left to kick off the wall, you immediately press Right, you'll slowly creep your way up the wall where you'll discover that it has no top, and that means...

You fall right through it onto the platform below.

But be aware, you'll stir up quite a few enemies in the process.