Critics received Ender's Game well. The novel won the Nebula Award for best novel in 1985, and the Hugo Award for best novel in 1986, considered the two most prestigious awards in science fiction. Ender's Game was also nominated for a Locus Award in 1986. In 1999, it placed No. 59 on the reader's list of Modern Library 100 Best Novels. It was also honored with a spot on American Library Association's "100 Best Books for Teens." In 2008, the novel, along with Ender's Shadow, won the Margaret A. Edwards Award, which honors an author and specific works by that author for lifetime contribution to young adult literature. Ender's Game was included in Damien Broderick's book Science Fiction: The 101 Best Novels 1985–2010.New York Times writer Gerald Jonas asserts that the novel's plot summary resembles a "grade Z, made-for-television, science-fiction rip-off movie", but says that Card develops the elements well despite this "unpromising material". Jonas further praises the development of the character Ender Wiggin: "Alternately likable and insufferable, he is a convincing little Napoleon in short pants."
The novel has received negative criticism for violence and its justification. Elaine Radford's review, "Ender and Hitler: Sympathy for the Superman", posits that Ender Wiggin is an intentional reference by Card to Adolf Hitler and criticizes the violence in the novel, particularly at the hands of the protagonist. Card responded to Radford's criticisms in Fantasy Review, the same publication. Radford's criticisms are echoed in John Kessel's essay "Creating the Innocent Killer: Ender's Game, Intention, and Morality", wherein Kessel states: "Ender gets to strike out at his enemies and still remain morally clean. Nothing is his fault." Noah Berlatsky makes similar claims in his analysis of the relationship between colonization and science fiction, where he describes how Ender's Game is in part a justification of "Western expansion and genocide."
The U.S. Marine Corps Professional Reading List makes the novel recommended reading at several lower ranks, and again at Officer Candidate/Midshipman. The book was placed on the reading list by Captain John F. Schmitt, author of FMFM-1 (Fleet Marine Fighting Manual, on maneuver doctrine) for "provid[ing] useful allegories to explain why militaries do what they do in a particularly effective shorthand way." In introducing the novel for use in leadership training, Marine Corps University's Lejeune program opines that it offers "lessons in training methodology, leadership, and ethics as well [....] Ender's Game has been a stalwart item on the Marine Corps Reading List since its inception."