I remember Marvel did a Superman Expy and tried to rationalize his powers. (I think he was Kree? Gladiator or some such? With the big black mohawk haircut.)
Anyway, their take was that all his powers are really Telekinesis. TK force fields for toughness, TK to pick up a building by one corner brick, TK flight. I liked it, but not sure it covers everything.
Still, the Alan Moore-esque out-of-the-box noodling was cool. (His job on Marvelman Miracleman was inspired! [But, IMNSHO, nothing beats his run on Supreme!]) And of course, his 2-issue farewell to the Silver Age Superman is required reading for all superhero scholars.
I'm sorry, what was the question again?