The Blackout chapter contains 100 endings that you’ll need to go through manually (which involves pushing the same button for about five hours) in order to get to the true ending.
For your convenience, I compiled screenshots for every ending, which you can check out here:
Also, just because I like you a lot, I uploaded a save file for the PC version, where you can check out the true ending every time you go through Blackout again. There it is.