There are a lot of internal and external conflicts present throughout this book.  I'll try to list as many as I can. 

• Ender's conflict with Bonzo.  This one ends with physical violence and Bonzo's death. 
• Ender's conflict with Stilson.  Like the previous conflict, Ender kills his opponent.  
• Ender's conflict with the commanding "officer" of each army that he is a part of in the battle room.  When Ender first gets to Battle School, no army or commander wants anything to do with Ender. 
• Ender's conflict with the other commanding officers once he himself gets control of Dragon Army.  Even as a fellow commander, Ender doesn't immediately gain the respect of the other commanders.  Ender also struggles to gain the respect of the soldiers assigned to his army. 
• Ender's real conflict and battle against the buggers at the end of the book. 
• Ender's conflict with Graff and other Battle School adults.  Ender knows that he's being manipulated.  
• Ender struggles with being a "third."  
• Ender struggles to remain good while knowing that he must at times be violent and cold like Peter. 
• Valentine and Peter struggle against each other regarding their plan to influence politics on Earth.  
• Valentine and Peter have a fake struggle against each other as Demosthenes and Locke. 
• Every time Ender steps into the battle room, he is in conflict against another army.  
• Ender struggles with depression as a result of feeling extremely isolated throughout various parts of the book.  

In literature there are generally considered to be two main types of conflict: external and internal conflicts. External conflicts are issues that happen between the main character and outside forces; internal conflicts occur within the character. While this book certainly contains a lot of action, it is the internal conflict that gives it staying power. Here are a few conflicts of each type.

External Conflicts

• Ender's efforts to remain safe from bullies. This includes Bonzo, Peter, and other characters.
• The human race and its war with the Formics. This is the war that becomes the central external conflict of the novel.
• Ender's struggle to make friends despite his commanders' attempts to isolate him.
• Ender's struggle to win battles and progress through battle school.

Internal Conflicts

• Ender's fight to remain a child and hold onto his innocence after all the violence and conflict he endures.
• Ender's struggle to remain a good and caring person while also defending himself. He worries that all the fighting will force him into becoming more like Peter.
• Ender's struggle to forgive himself for what he is forced to do to the Bugger species.