Sheer size? Remember, a Microverse planet is the size of an atom
at best. Even Olympus Mons isn't a significant chunk of its home planet's mass, much less Everest. A Microverse mountain is
many magnitudes smaller than
a single atom to us. A Microverse
solar system,
empty space included, would probably be visible to the naked eye, (the width of a few hairs -
much smaller than the gleam on Tony Stark's armor) if the Earth-representative planet were the size of a carbon atom, but the individual planets, even if glowing like they were on fire, would still need an electron microscope to even detect as a kind of fuzzy dot, much less notice tiny surface features like mountains. (Meanwhile, at least one source I found claims that if the Earth were the size of a proton - which IIRC is supposed to be closer in scale to the Microverse - the solar system'd be
smaller than a hydrogen atom. Carbon atoms, much bigger, could still have around 7 trillion comfortably stuffed into the average printed period.)
What I'm trying to say here is that atomic scale or subatomic regardless, a mountain-sized energy blast would be utterly
negligible at the kind of size differential we're talking about.