If you not familiar with Simon Pegg's work with his longtime writing partner, then this may not be the place to start, depending on how much absurdity and embarrassment you are prepared to swallow at once. Other, potentially more accessible, places to dip in to their body of joint work include Shaun of the Dead (their homage to zombie movies), Hot Fuzz (a cop adventure send-up), and Paul (possibly one of the best films around with grey aliens in it).
With a plan for epic alcohol consumption to relive and fondly remember their possibly fictitiously golden youth, what starts out as a reluctant gathering of old pals takes a turn for the decidedly odd somewhere in the middle. Scenery-chewing performances from much of the cast make this a fun movie to watch, and Pierce Brosnan's appearance is particularly memorable. Don't expect a neat, happy wrap-up kind of ending, but enjoy the mind bending ride while it lasts.
For those who say celebrate the work but not the author, the movie is a resounding success. Although no movie has the time to render every part of this beloved coming of age story, this one certainly hits the main features quite serviceably. Asa Butterfield renders an entirely believable Ender tortured by the decisions he is compelled to make. The mind game is given short shrift, but so is everything else in the story. The number of battle room games actually shown is small, but the essential lessons are well distilled. Harrison Ford as Graff does well, and the diverse supporting cast from Anderson to Bean to Rackham help to make it all come alive.
I still recommend reading the novel first, but this is a wonderful treat for the fan.