11-11: Memories Retold has 7 endings, and you can easily get all of them by replaying last two chapters few times and changing choices in them.
By playing as Harry in Consequences chapter you are given the important choice, which leads to two different variations of the last chapter. The first variation (Harry choose to go home to Julia) has 2 endings: Lone Avenger and Forgiven. The second variation (Harry choose to save Kurt) has 5 another endings: Betrayal, Sacrifice, Revenge, Grudge and Peace.

For Lone Avenger ending:
Just choose "Shoot Barret" when you'll be given choice.

For Forgiven ending:
"I want answers, Barret. ANSWERS!" ->
"I need to know what happened to Max." ->
"This is what I came here to do." ->
"I see your men, Barret, but I do no care." ->
"I am DOING this for Katrin! For Lucie!" ->
"DO NOT SAY HIS NAME!" ->
"I have no choice. I must finish this."

First four choices don't matter so choose any you want. The fifth choice ("Sir, did you kill that prisoner?" or "Think of Katrin. Think of Lucie.") gives the fork for endings.

For Peace ending:
"Sir, did you kill that prisoner?" -> "Lower Harry's gun"
OR
"Think of Katrin. Think of Lucie." -> "Lower Harry's gun"

For Sacrifice ending:
"Sir, did you kill that prisoner?" -> "Just get on the knees. Please, sir." -> "Shoot Barret" (Or on the next choice)

For Revenge ending:
"Sir, did you kill that prisoner?" -> "Just get on the knees. Please, sir." -> "Sir, please. Tell him what he wants to hear" -> "Sir. He lost his SON!"

For Betrayal ending:
"Think of Katrin. Think of Lucie." -> "The war is over, Kurt." -> "Shoot Kurt" (Or on the next choice)

For Grudge ending:
"Think of Katrin. Think of Lucie." -> "The war is over, Kurt." -> "Kurt, get on your knees." -> "Kurt, it's over."