I/O revision II [Visual Novel; English, Japanese]

Recommended route order: A->B->C->D->E->C'->D'->B'->A'->E'

Before beginning the walkthrough, there are several important things we need to tell you. Please read the below carefully before starting the walkthrough.

0.1 and 1.0 Endings
Initially, you can only see the 0.1 Ending of the initial four routes. You need to see the 0.1 end of certain other routes to see the 0.1 Ending of the route. Getting all 1.0 Endings is necessary to clear Route E. So by this logic, if you play the routes according to the above route order, the first 1.0 ending you should be able to see is Route C's.

Getting the 0.1 Ending sets the route's value to 1, while getting the route's 1.0 Ending sets the route's "complete" value to 1. While the route's value is permanently 1 after you get the 0.1 Ending, its complete value can be set back to 0 if you get a Bad Ending on the route (and if you get the Good Ending again, it will be set back to 1). Here's the list of the Endings you need to see other endings.

A 1.0= Requires C 0.1
B 1.0= Requires D 0.1
C 1.0= Requires B 0.1
D 1.0= Requires A 0.1

If you do not have all 1.0 Endings, then you cannot clear Route E.

We recommend playing it in this order: A 0.1 Ending->B 0.1 Ending-> C 1.0 Ending->A 1.0 Ending-> D 1.0 Ending-> B 1.0 Ending->Start Route E
Explanation of the Defrag System
Each of the initial four routes has certain lines and scenes "locked" that are only avaliable to read once you have obtained certain other endings. Seeing these scenes is necessary to get 100%, and contain information not found in other parts of the game. While you can play them at any time, we recommend going through them before starting Route E.

Initially locked scenes will be represented on the Defrag icon with "X" covering certain blocks. Once you obtain the necessary ending to see that content, the "X" will disappear. If you turn your complete value back to 0 after it's been set to 1, then you will see the "X" return. To get rid of the "X", set the corresponding route's complete value back to 1.

Likewise, Route E initially has multiple locked scenes that are only unlocked after obtaining Route E's ending and clearing Route D'.

Walkthrough:
Note: Routes A'-E' are linear, and thus have no choices.

Note 2: A choice marked with an * has no impact regarding what ending you get.


LogIn
A boy who left behind his innocence: Route A
A young woman followed by companions: Route B
A young woman standing in solitude: Route C
A man with great strength: Route D

Route A:

*Tell her about what you saw.
She's the girl who missed the bus.
*Too troublesome. Don't mention it.
*Ask her why she's meddling in my affairs.
*Try to login
Yumi, that is to say, Shinozuka Mayumi.
Can't take her with me, no matter what.


Route B:
*Display magnamity as a leader.
*Consult your friends indirectly.
*(It doesn't matter what order you pick the four choices when you meet Nergal)
*Seek everyone's cooperation.
Escort her yourself.
Let's accept everyone's resolve.
Believe in ourselves.
Let's go together
Pass...


Route C:
*Try calling out to him.
Now's not the time.
Don't kill...!

Route D:
*Ask the woman
The information is right. But...
That's impossible.
Wait to strike.
Trust...

Route E:
............
*Is there no other way?
*I'm looking down...
Wants to wake up
Here!
Is all of them


Bad Ending Walkthrough

Bad Ending #1:
She's the one I saw at the front of the school.
Sami, that is to say, Shinozuka Masami
(Whatever you pick for the final choice doesn't matter)

Bad Ending #2:
Take her with me.

Bad Ending #3:
Have Kosuke escort her.
Give her a day.

Bad Ending #4:
We really can't risk the danger.

Bad Ending #5:
Withdraw here and now.

Bad Ending #6:
Split up into two teams.

Bad Ending #7:
Hold...

Bad Ending #8:
Let's do this. Let's save...

Bad Ending #9:
Stop...

Bad Ending #10:
Trust...

Bad Ending #11:
That might be it.

Bad Ending #12:
Unleash a salvo

Bad Ending #13:
... is dead.

Bad Ending #14:
That's right.

Bad Ending #15:
Get Bad Ending #7, save it to the system data, and play up to the scene "memento mori" in Route E.

Bad Ending #16:
Get a bad ending on any route other than B or E, save it to the system data, then play up until the scene "I/O" in Route E.

Bad Ending #17:
Wants to remain asleep
Somewhere other than here?

Or

This one!
(Seeing both versions is necessary for 100% completion)


MATRYOSHKA 100% guide
The late Route E scene, MATRYOSHKA, requires you to go through it several times with different conditions in the scene.
To get 100% in the scene, you need to pick both options of the scene, then you must view it after having set C_complete = 0 on (get Bad Ending #9 and save it to the system data), and then a second time after having set A_complete= 0 on (get Bad Ending #2 and save it to the system data).