Trivia: When Loki is grabbed by the Hulk and repeatedly smashed into the floor, Tom Hiddleston had a rope tied around his ankle which was pulled to achieve the effect. Although, Tom was told that the rope would be pulled while speaking to the Hulk, he was never told when the rope would be pulled so his reaction to quickly be pulled down was real.
Trivia: For the post-credit scene where the group are eating shawarma together, Chris Evans had to wear a prosthetic jaw, because he had grown a beard for another movie and couldn't shave it off. It's also why he's resting his head on his hand through the entire scene, conveniently covering up most of his face.
Trivia: The collector cards owned by Coulson are actually covers of some Captain America comic books.
Trivia: The photo of Cap in Tony's tower has the number #25 - the issue number of the comics in which Captain America dies.
Trivia: The first movie to ever gross over $200 million domestically in its opening weekend. (And somewhat coincidentally, it was released almost exactly ten years to the day after "Spider-Man" - the first movie to gross over $100 million in its opening weekend, and also based on a Marvel property).
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