To unlock the "I'LL BE BACK" trophy in Detroit: Become Human, you must make sure that Connor is killed whenever possible. You MUST do this from a New Story and play the game through in order.
I tested this in multiple playthroughs and the trophy did not unlock until I started a new story.
However thanks to comments on this solution from Rav3nDK_72
it appears that you can go back several chapters to correct a mistake, as long as you continue to "overwrite" the story by playing every subsequent chapter up to the point you previously reached. A hypothetical example: if you realise something is up during Chapter 10 due to a decision made in Chapter 6, you can't go to Chapter 6, change the decision, and hop back in Chapter 10 expecting things to be different. Chapter 10 will still be "reading" the game's current state of play from Chapter 9. You have to "overwrite" Chapters 6 through 10 in order for Chapter 10 to reflect your altered decisions.
As multiple deaths lead to a very singular story experience and locks you out of a number of other trophies, I suggest leaving this until last. If you've done everything else you need to with Kara and Markus you can speed this playthrough up considerably by
In addition, you need to make Hank really hate you before you get to "THE BRIDGE". Naturally that's going to make it pretty impossible for you to get this:
Here is an optimal playthrough of the game to get this trophy as quickly as possible, bear in mind that you'll be locked out of a vast number of other trophies if you still need them.
Oh, one more thing - there's a crucial choice to make in LAST CHANCE, CONNOR that nearly every guide out there seems to have failed to mention, which I learned far too late... see below in the spoiler tags!THE HOSTAGE - Death Opportunity
SHADES OF COLOUR
A NEW HOME
There's no more efficient or useful way to play through BROKEN
, it's short anyway, so just follow your prompts and make your choices.THE INTERROGATION - Death Opportunity
FROM THE DEAD
WAITING FOR HANK...
ON THE RUN - Death Opportunity (Plus, Speed Up Your Playthrough)
THE NEST - Death Opportunity
TIME TO DECIDE
SPARE PARTS - Speed Up Playthrough Opportunity
THE EDEN CLUB - Speed Up Playthrough Opportunity
THE BRIDGE - Death Opportunity
THE STRATFORD TOWER - Speed Up Playthrough Opportunity
PUBLIC ENEMY - Death Opportunity
CAPITOL PARK - Speed Up Playthrough Opportunity
FREEDOM MARCH - Speed Up Playthrough Opportunity
LAST CHANCE, CONNOR - Death Opportunity
CROSSROADS - Death Opportunity
NIGHT OF THE SOUL - Likely Trophy Unlock
It seems almost unanimous across various sites that the trophy will unlock at this point, as it did for me, despite the fact that Connor still has remaining chances to die. Perhaps "...before the end" in the trophy description means "...before the last chapter". But in case it doesn't unlock for you (or this early unlock is a bug that gets patched), here's the final opportunities.BATTLE FOR DETROIT - Two Death Opportunities
It's worth noting that you'll also get the following trophy in the final chapter if you haven't already, so it's worth seeing through:
As always, the trophy will unlock when you reach the flowchart at the end of the chapter, whether that's after NIGHT OF THE SOUL or BATTLE FOR DETROIT.