Bad end means that you made the wrong choice and the story ends there.
Story continues means you made the right choice and didn't die! (yay!)
No comment has no real effect on the story other than each choice presents different dialog.

First choice
1: Praise her
2: Exclaim in surprise
3: Be at a loss for words (picked if you let time run out)

Second choice
1: Sorry, I have no idea what you just said.
2: Of course I have. I know all about it.
3. Let time run out

Third choice
1: Saying words of thanks
2: Blushing shyly and looking away (picked if you let time run out)
3: Talking about my memories of Sorano

Fourth choice
1: Ask Reina about the image file Sorano sent me.
2: Ask Reina about Haruna.
3. Ask Reina about her past. (picked if you let time run out)

Fifth choices
1: Chase after Reina. (story continues)
2: Don't chase after Reina. (bad end) (picked if you let time run out)

Sixth choice
1: No (bad end) (picked if you let time run out)
2: Yes (story continues)

Seventh choice
1: Run (story continues)
2: Don't run (bad end) (picked if you let time run out)

Eighth choice
1: Don't stop Haruna. (picked if you let time run out)
2: Stop Haruna.

Ninth choice
1: Help Reina fix her balance.
2: Just let her hold on to my arm. (picked if you let time run out)

Tenth choice
1: Thank you Reina.
2: Sorry Reina.
3. Let time run out

Eleventh choice
1: Thumb/Index finger
2: Middle finger/Ring finger/Pinky
3. Let time run out

Twelfth choice
1: Can't bring myself to sacrifice her (bad end) (picked if you let time run out)
2: Sacrifice Sorano (story continues)

Thirteenth choice
1: "...I heard Sorano's voice." (story continues)
2: "...Nah nothing, I probably just imagined it." (bad end) (picked if you let time run out)