Continuity mistake: Throughout the film, Tony Stark's chest ring can be seen glowing through his shirt except for two occasions when it's suddenly off - after Loki escapes from the helicarrier, and when Loki and Tony Stark are talking in Stark tower, even when he's wearing the same shirt. (01:35:30)
Continuity mistake: When Hawkeye is breaking onto the Helicarrier, he and some snipers break down a duct cover and enter. When the cover lands on the floor, it is resting away from some pipes with some slats missing. As soon as Hawkeye enters the duct, the cover is now resting against the pipes, and the slats have reappeared. (01:10:35)
Continuity mistake: When the plane lands on the aircraft carrier, it is about to land on a yellow mark on the ground. The angle cuts and it's now landing in front of it. Then from the aerial angle it lands in the middle of both lanes, but a frame later it's on the right lane. Finally, the landing signal officer swaps from standing in front of the plane waving his arms, to several meters behind standing still. (00:31:45)
Continuity mistake: When Iron Man and Thor are fighting, Thor grabs Iron Man's wrist at one point. In the next shot, he is holding him by the forearm. (00:46:55)
Continuity mistake: When Tony goes after the nuke, there is a huge cut visible above his right eyebrow (or viewer's left). Later on after his face mask is removed, his right eyebrow is completely visible in the shot, even with the helmet in the way, and the cut is nowhere in sight. (02:00:00 - 02:03:00)
Continuity mistake: During the big battle against the Chitauri, Captain America is zapped with a blaster bolt. When Thor helps him to his feet we can see a significant amount of damage done to his suit, just below the star on the right hand side. But later on after Iron Man destroys the Chitauri ship with the nuke, the damage is completely gone. (01:59:25 - 02:02:40)
Continuity mistake: When Steve Rogers first meets Bruce Banner, Rogers' hair keeps changing between being neat and being blown apart, depending on the angle. (00:32:35)
Continuity mistake: When Thor lands beside the overturned car on the Park Ave viaduct in front of Grand Central, the car has a dent between its fender and tire, but in the next closeup that dent has vanished. (02:04:10)
Continuity mistake: During the battle of New York, Thor has just landed next to an upturned silver car. The rubble around the car changes/moves. The most noticeable is one wedged next to the front right wheel. The piece becomes much bigger in the next shot. (01:50:25)
Continuity mistake: When Steve and Coulson land on the Helicarrier, you can see two wings on the edge of the Quinjet they were in and they are both closed up. Next shot, as Romanoff approaches the Quinjet and Steve and Coulson exit, we can see one of the wings is completely open. (00:30:35)
Continuity mistake: When Maria Hill is being attended to after she gets hurt, her earpiece is on the left side of her face. In the next shot she is talking to Nick Fury and her earpiece is on the right.
Continuity mistake: In the scene where Loki escapes with Hawkeye and Agent Hill is chasing them, she does a 180° spin and ends up face to face with Loki's driver. She shoots through the glass and you can see the bullet hole, but during the rest of the scene, the hole is gone. (00:09:25)
Continuity mistake: After the big battle, Iron Man lies on the street when Capt. America, all dirty and messy, says "We won." Iron Man sighs in relief and rests his head on the pavement. A frame later, from a wide angle, his head is raised, plus Capt. America's face is clean and his hair is brushed. (02:08:30)
Continuity mistake: When Agent Coulson is dying, Fury grabs Coulson's chin with his hand. The hand disappears in the angles shot from behind, only to reappear in the front ones. (01:28:05)
Continuity mistake: While Loki lies on the floor and talks about the Tesseract, bushes appear/disappear by his left side between shots. (00:43:00)
Continuity mistake: For a brief moment during the battle at the end, the scar on Tony Stark's left cheek vanishes after saying "I will, roger that" to Hawkeye. It reappears shortly afterwards. (01:54:15 - 01:54:55)
Continuity mistake: When the Helicarrier is about to take off, Banner and Rogers are still at the edge of the landing strip, identified by the yellow SHIELD logo and the jet that Banner is checking out. But the shot hangs on Romanoff for a second, and when it cuts, Banner and Rogers are instantly at the very edge of the ship, a good 50 feet away from where they were a second ago. (00:32:55)
Continuity mistake: Just after Dr. Banner asks Nick Fury how many spectrometers the Helicarrier has access to, he takes off his jacket, rolls it up, and puts it under his arm. In the next shot, without Banner moving, the jacket is suddenly draped over his arm. (00:34:15)
Continuity mistake: When Tony arrives at Stark Tower, he and Pepper share a bottle of champagne. In the shot where he says "Next building is going to say Potts on the tower", Tony's champagne glass is in his hand and there's no sign of another glass several inches either side. In the next shot, Pepper's glass is suddenly 2 inches away. (00:24:30)
Continuity mistake: When Captain America, Black Widow and Hawkeye are fighting their way through the Chitauri in the S.H.I.E.L.D. jet, one shot shows the Chitauri blasting at the jet causing part of the front of one side to get blasted and a burn mark is left on the jet. A few seconds later, Loki blasts one of the engines and the burn mark on the front of the jet has vanished. (01:40:35)
Answer: While Loki is not immortal, he's just as powerful as Thor, and many mortals would consider him a God as well. Loki is actually a Frost Giant taken in by Odin, but is just as invulnerable to many attacks. There may also be an element of magic involved in his survival as well.
Bishop73