Thus begins one of the best discussions I have read on what makes Metroid and Super Metroid so good.

And then, something curious happens. A bomb placed haphazardly at the bottom of a vertical shaft explodes… and takes with it a chunk of the floor. This surprises me, because while I know certain floor and wall tiles are vulnerable to explosions, those had always been set apart with cracks. This section of floor, on the other hand, didn’t look any different from the rest of Norfair — an extrusion of what appeared to be purple bubbles of different diameters. Curious, I let the floor regenerate and bomb it again. And again it boils away beneath my bombs. So, I start rolling around to see what else I can destroy. A few more floor tiles evaporate, but ultimately this leads to nothing. Still, I’ve made an important discovery. I run to a nearby room and start bombing everywhere: on the floor, in the air, against the walls. And here’s where it all pays off, because a bomb placed at head height against a nearby wall as my spherical hero is lifted into the air by explosive force shatters a block. I bounce into it, Samus still tucked into a ball, and roll until I can go no further. Another bomb clears this latest obstruction, and another, and another, and suddenly I’ve uncovered an entirely new room. I’ve cracked the mystery of Zebes.

Bombing in Norfair