That was a nicely energetic battle report!
I visited Iwo Jima in 2023, what struck me about getting off the beaches was how it felt like going uphill to a flat shelf, that led to another upslope, then another, all nicely in view of the Japanese machine gun positions waiting for you at the top. And the sand is very loose, so you're sliding down as well. It's hard to express in photos as the black sand doesn't show how high or steep those slopes can be.

Suribachi from Green Beach

Saw these on the ground near the foliage, no I didn't touch them. You don't touch any of this stuff.

View from the top. None of this terrain is actually flat. It's all slopes and once you crest the top... it's uneven and hilly with lots of places to put hidden holes in the ground.