At the end of part 1, Kanja-Ro says that Green Lantern's energy beam bounced off the deflector shield of an attacking ship and hit a volcanic fault line. In the recap in part 2, Kanja-Ro says it was a stray shot by Green Lantern Stewart that caused the destruction of Arcturus 4.
Kilowog's ring changes hands during the bar fight when he catches a fellow Green Lantern.
Kanja-Ro says that Green Lantern Stewart's errant beam caused the destruction of Arcturus 4, along with three billion lives. Yet, the destruction is revealed to be a farce. It's hard to believe that no one from any of the other planets in the system investigated or that none of the inhabitants of Arcturus 4 made themselves known.
With no air on the moon for Hawk Girl to flap her wings, she shouldn't be able to stop herself from spinning.
Hawk Girl shows up on the moon in an Ajuris 5 spacesuit. Ajuris 5 just happened to have a suit not only with wing holders, but ones to handle the design of her wings?
Why is it only J'onn J'onzz and Superman noticed the moon hadn't flown off?
It's been established the Green Lantern can't move the speed of light, so leaving the Green Lantern home world, he creates a bubble to carry the others, with air, but it's not enough air to make the journey back to Earth.