Whatever the punching machine was made of, it was probably the strongest material ever known to man — no, even known to gods. Hundreds have already struck it, and yet it hasn't even caved in once and just continued to tank in everything.
Riley had been observing everyone hitting the machine from the start, and he had deduced that most of the themarians he had met would pass the 15th floor with no problem at all. But of course, it doesn't mean that they had the power to become gods — almost all the gods who have hit the machine had other abilities other than just being extremely strong; like Miss Pepondosovich, who was just pulling anything and everything from a hat that disappears and appears as she willed. And even him, who now even had the ability to somewhat stop time.
But Esme, her energy projection was subpar compared to other themarians, and flight is not really special since everyone can do it nowadays.