The last part of The Following was a driving against the clock type of mission on a long distance then a climbing on a tower building at the dam
Took me a few tries (to find the best path for driving my buggy , and finding the best way to climb the tower before the end of the countdown) but finally did it.
It's then in that location that you enter that you'll decide what will be the ending (as at some point you'll be given 2 choices by
the sexy woman you'll meet, warning nsfw screenshot
)
I went for what seemed to be a bad ending (you detonate nuke, so you die, everyone else die in both Harran and in the countryside).
Checked google for what was the other ending and it looks like it was an even worst ending as you get a boss fight and if you survive you can leave the place ... but soon transform into an infected (so can't even save you friends back in Harran) and start to spread the virus worldwide and kill everyone.
At least the ending i got seemed to have the virus maybe "contained" due to the killing of the whole region by nuke.
Basically the conclusion of Dying Light + The Following is that everyone dies or everyone dies.
Sad thing is that you can't try the other ending without recompleting the whole The Following campaign, as loading the post-end saved game does not allow you to access the last mission again , at least i have still lots of challenge missions to complete both in Harran and in the countryside.
Wish i had selected the other ending so i could have gone through that boss fight.