I think the atmosphere thing was that it was specifically an artificial Kryptonian atmosphere that was neutralizing his powers, combined with Kryptonian super-tech. The Kryptonian doctor did say that they had neutralized his powers, IIRC, so presumably they had somehow keyed it to the Kryptonian environment/atmosphere while he was knocked out during his initial adaptation.
As for how Zod got the powers too, I'm assuming there was a deleted scene where Kryptonian super-tech was used to accelerate the process, possibly involving the blood sample they took from Superman.
As a side note, couldn't another scoutship with a genesis chamber have been found, to restore the Kryptonians? Krypton sent out some huge number of them, after all. If the one on Earth survived, I doubt it was the only one.
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Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.
As for how Zod got the powers too, I'm assuming there was a deleted scene where Kryptonian super-tech was used to accelerate the process, possibly involving the blood sample they took from Superman.
As a side note, couldn't another scoutship with a genesis chamber have been found, to restore the Kryptonians? Krypton sent out some huge number of them, after all. If the one on Earth survived, I doubt it was the only one.
-----
Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.