I only played for like 3hours and got seriously discouraged after dying like 15 times in the same area with 1 clicker and 5 or so runners. I finally did it but it felt so messy.
I had a tough time in the beginning as well because I was trying to figure out tactics, buttons, and everything else against some long odds early on. It's kind of how the game is though. It routinely puts in you those desperate kind of situations where you might not have enough ammo or supplies to survive a full on encounter. Some of the best encounters in the game were those times when I had next to nothing and had to figure out a way to slip through undetected.
And also, if you're referring to the spot where you're with Tess and Ellie and leave them behind to clear the area below, then yes, that part was a major PITA for me as well. Took me at least five tries before I barely scraped by that area.