Why could Hal Jordan use his ring to contain the Center's bright yellow explosions when Abin Sur specifically said he couldn't use that same ring to block the explosion from Hal's spaceship because the blast was yellow?
In the comic the yellow energy that downed Abin Sur was from the Center not from the shuttle exploding and the explosions were more orange.
Speaking of Hal Jordan, did anyone else note this concept of an Air Force fighter pilot who's not willing to kill, and respond with a "what a minute, what?" Fighter pilots have always been in charge of very expensive, very dangerous pieces of machinery, and military establishments without exception select very rigorously for certain traits — not just eyesight, reflexes, and hand-eye coordination, but also a certain psychological profile. They want hypercompetitive, highly aggressive personalities with the "tiger instinct" and few inhibitions about violence, "gunslinger personalities" who are eager to carve another notch on the butt of the pistol. How did this version of Hal Jordan ever make it through the psychological screening?
In the comic Hal would act as a decoy and lead enemy pilots into the guns of his comrades, so he wasn't useless as a pilot, just very reckless.
Psychological screening, even that conducted by the U.S military, is not foolproof. Nor can psychological profilers necessarily capture every single nuance of human personality, thought and experience through a psych test. Could be that Jordan matched enough of the personality traits during the screening process, but couldn't bring himself to do it when finger-on-trigger time came for real. He probably wouldn't be the first or last.
Also, this is the fifties we're looking at here; were the screening processes as rigorous as they are today?
And as Hal later demonstrated, "unwillingness to kill" does not equal "unwillingness to fight when necessary".
My problem is not that they wound up with a fighter pilot who was unwilling to shoot people (though it's a bit of a stretch), but that after he demonstrated that unwillingness, they still kept him. Yes, yes, he was setting up the enemy pilots for his comrades to shoot down (which just makes him look hypocritical; apparently it doesn't count as killing people as long as he gets someone else to pull the trigger) but generally the military takes a really dim view of people who refuse to fire their weapons in combat.
My personal hand-waving is that Hal's simply that good at flying that they didn't want to lose him despite this, and / or only kept him on the front line until they could find something else for him to do.
In the book, there's a poster for the Mercury Program seen on a classroom wall during the montage at the end. I get that the expedition to Mars was a secret, but if they have that tech, and The Space Race is as serious as in our world, why have a program just devoted to getting one guy into orbit when they already almost sent four people to Mars?
The flight to Mars, let's not forget, was a dismal failure, with one of the crew members going completely mad in the process and the other two eventually blowing themselves up; they have might decided to adopt a 'walk-before-you-can-run' approach to sending people into space. Plus, that mission IIRC was done in secret, whereas the new approach is presumably to be more open, partly because it's PR opportunity against the Reds but also as a reflection of the more secretive and paranoid Fifties becoming the more (publicly, at least) open and relaxed Sixties.