AAs the film does involve Roswell/Area 51 and saucer-shaped spaceships, it has largely been disputed that the body that is found at Roswell/Area 51 and in the temple at the end are aliens. However, in the film, Oxley corrects Mutt, when asked if they are aliens, by saying, "Interdimensional beings, in point of fact." He also tells Indy they come from "the space between spaces." The original concept that was talked of for many years was that they would be aliens, since the film took place in the 1950s timeframe, planning to utilize the concept of aliens and B-movies. However, according to the DVD documentary, Steven Spielberg was against the concept, explaining he had done his 'alien films' already with Close Encounters of the Third Kind and E.T.: The Extra-Terrestrial. The 4th film was still favoring aliens when Independence Day came out, which Spielberg used as an example to say that the 'alien' angle would probably not work, since ID4 used it in a very entertaining way. Some years after this, Lucas proposed dropping the alien concept, and asked Spielberg about the idea of making the aliens into 'inter-dimensional beings.' Instead of creatures travelling through outer space, they'd travel between dimensions. To keep the 'Area 51' aesthetic, the inter-dimensional beings were made to resemble aliens. In "The Complete Making of Indiana Jones: The Definitive Story Behind All Four Films," George Lucas explains that for the inter-dimensional beings, time functions differently for them and us. What could be hundreds of years to us could be minutes or hours to them.
AThe film has mostly received positive reviews. Rotten Tomatoes reported that 77% of critics gave the film positive reviews, based on 245 reviews (Avg rating being 6.9/10), with a 61% (US) rating from selected notable critics.
AMost notably, there are, as Indy puts it, "big damn ants" that chase the heroes and villains as they fight one another through the jungle. Indy identifies the ants as "siafu," which are native to Africa and can't actually move as rapidly as seen in the film. They are commonly known as army ants. Mutt has a run-in with scorpions--a possible nod to what his "feared" critter might be and which recalls the tarantulas that covered Sapito in the opening of Raiders. And of course, there is a snake. Finally, there is a troop of monkeys that help Mutt and attack the Russians.
