Ender Wiggin Movie Vs Book

In a world where little kids have to fight an alien race that seeks to destroy the whole entire world. One six year old kid must save us all, his name is Ender Wiggin. A race of aliens known as the Buggers seek to destroy earth and make it their colony, they are defeated due to a single commander, Mazer Rackham. By the threat of a third invasion occurs the international fleet finds that children can handle information the best, they start on training these kids to be the best combat specialists. Ender is chosen and trained, and surprisingly to the IF he is there best chance of winning this war. Overall the book provides the important details and plot points that make it the better of the two interpretations.
Ender’s game, like most stories follows pretty basic steps, from the

Firstly the main plot is derived from the book. The main battles that they had in the book were kept in the movie for the most part. Finally the final “training”/battle was kept mostly intact. These are probably the most important parts of this story which is good that they left these scenes in. They left most of the main characters in (spirit at least) the movie which provided a helping hand to any confused fan of the book who was trying to figure out what was actually going on. Really the movie is more of a summary of the book, rather than a tie in. One good thing about the simplicity of the movie was the fact that it wasn’t really that hard to follow, which is good for the average movie goer who wants a decent movie to sit down to that looks good and enjoy popcorn with.
Where do I even start with the difference between the book and the movie. Firstly the movie places most of the side characters out of order when they show up, for example when ender is launching off for the first time to battle school he meets Alai and Bean on the launch. In the book Alai is already in salamander army to begin with in the story. Ender doesn’t