"When you are done, I will complete my task and deliver you on to darkness," Anubis told Laura. He never accomplished his task though, because Laura's task got bigger than that of Anubis in American Gods. She got a second chance at life, which she has used to prove that humans don't need the gods to be good people.
Laura Moon was transformed into one of the most powerful characters in the show although her transformation had some glitches. When she died the second time, she went to purgatory despite the fact that she didn't believe in anything, which doesn't add up. The show then redeemed her into a strong woman independent of Shadow Moon but not without leaving lots of gaps in her many lives - and these are the biggest ones.
How Did She Stay Sane & Mentally Capable?
Mad Sweeney's coin only managed to save Laura's heart, the rest of her body was full of bugs, including her head. When she came to Audry's house, her body was already falling apart. Mr. Ibis and Anubis patched her up better than Audry did but no one reversed the rot.
Wednesday warned her that her body would not hold up for long as she continued Zombie-ing around. She didn't have any blood flow either, because there was no bleeding when her limbs fell off after the crash. However, she never lost her mind all that time that she lived as a zombie. So, how did a brain being eaten by bugs and without any blood supply stay intact?
The Coin Finding Laura's Heart But Not Sweeney's
Laura disagreed with the idea of her heart being weighed against a feather and she was right, there was no way she could have survived that test. Then Shadow dropped the coin on the grave, and it somehow managed to locate her heart.
When Laura placed the coin in Sweeney's hand while trying to revive him, it just rolled away and didn't seem interested in finding Sweeney's heart. It doesn't make sense how a coin that went through a sealed grave, through a coffin, and found its way to a dead woman's heart, failed to find the heart of its owner when actually touching him.
Laura Seeing The Light Around Shadow
When Laura came back to life the first time, she said Shadow was the reason why she came back but Wednesday proved that that wasn't really true. Actually, Laura never loved Shadow to begin with. She got him to steal from the casino before leaving him in trouble when he was caught, and then cheated on him with his best friend when he went to prison.
When she was reanimated, she got a heartbeat when she kissed Shadow but he rebuffed her saying he wasn't her puppy anymore. She continued to see a light around Shadow and could feel his presence from far away, although Shadow didn't love her either. So, where did that connection that enabled the heartbeat and the light come from and why did it disappear later?
Laura's Super Strength
When she was reanimated, Laura was so strong that she could lift a car with her bare hands. She kicked Sweeney into the air sending him flying for several feet. There is no way to explain Laura's super strength and why it disappeared though. Even Sweeney didn't have such strength when he had the coin yet all his systems were working perfectly.
Laura had no muscles since her limbs were only being held together by the thread from the funeral parlor. Her limbs were literally falling off because the bugs had eaten through the joints. She wasn't eating either, because the only thing she could taste was a cigarette. With that combination of limitations, Laura wasn't supposed to be able to walk, leave alone lift cars.
Killing Argus Reversing Laura's Rot
Argus was the god of Surveillance that betrayed Wednesday in the second season. Wednesday had promised Laura that he would save her life if she killed Argus, but he was just lying as always. Argus was obviously in distress by the time Laura killed him and there was nothing to suggest that his death helped Laura in any way.
He wasn't in a position to save himself, leave alone bring Laura back to life. However, after Laura killed him, her rot was temporarily reversed, but not stopped. The reversal was obviously not Wednesday's doing which leaves the question of how killing Argus temporarily saved Laura.
Her Short Life After Removing Sweeney's Coin
Laura's life after her reanimation depended on the coin being in her heart at all times. When the coin fell out after the accident in the first season, Laura died immediately although her body didn't disintegrate at the time. However, when she cut her chest open and removed the coin, Laura miraculously stayed alive for long enough to place it in Sweeney's hand before she fell.
There is no way to explain the short life between the time Laura removed the coin from her heart to the time she finally fell on the ground since the coin was no longer in her chest. It is not clear why she disintegrated into dust this time around and not during the accident either.
Laura's Second Coming Back To Life
Laura didn't trust Samedi, the Voodoo priest, which is why she didn't drink the potion when it was given to her. Samedi's assistant also made it clear to her that the magic in the potion was for Laura only and could not work on Sweeney. However, Laura never got the chance to drink the potion before she fell and disintegrated into dust.
It only worked after Gilbert, the graveyard maintenance attendant, accidentally stepped on it causing it to mix with Sweeney's blood. By that time, it is hard to believe that all of Laura's dust was still there, considering the time the dust lay there and her dress having been removed. It is also hard to believe that the potion somehow gathered her scattered dust together and brought it back to life.
Laura Going To Purgatory
The basis of American Gods is that the gods only exist if you believe in them. Laura Moon didn't believe in any gods. Having been killed by a war god led her to acknowledge the existence of gods but she has never professed her faith in any of them.
Purgatory is an aspect of the afterlife associated with the Christian faith, one that Laura didn't subscribe to. When she died the first time, she never went to Purgatory. Instead, Anubis wanted to send her straight to the darkness because she believed in nothing. So, why Purgatory in the third season?
Laura's Sudden Ability To Wield Gungnir
Gungnir needed lots of strength to wield, leave alone get a perfect aim on it. Even Shadow who is physically stronger than Laura struggled to lift it. When Laura practiced her aim without the coin, she could hardly throw it a few feet away because she just wasn't strong enough. When she grabbed the gold coin, she could suddenly hit her target. The gold coin could explain her aim because it came with good luck but that doesn't explain the super strength.
Laura Saved By The American Motel
The power of the gods couldn't work in American Motel, as Mr. World explained, but that doesn't apply to humans. Czernobog couldn't swing his hammer at Laura in the motel because his power as a god was limited. The same doesn't apply to his strength as a human though.
Czernobog is a big guy that could easily kill Laura even without the hammer. The truth was that the Old Gods didn't need their powers to kill Laura Moon. Limiting the power of the gods doesn't explain why none of the Old Gods made an attempt on her that day. The gods also had the time to just pull her out of the motel and kill her if they wanted to.