Finished the game earlier today. Enjoyed it completely. The expanded traversal and transport options made the game feel larger than previous games. The stealth was both useful and fun to pull off. I only really hit a few rough spots, mainly one where two armored mini gun foes where in the same location.
The story went in a predictable, yet satisfying way and I'm okay with the way they ended Nathan's story. TBH, I would be okay if they take the lead-in at the end for a new series.
I lucked out and had a grenade launcher in the spot you mentioned.
I could have stayed up very late for the last couple of chapters tonight, but I'm saving them (mostly because I have to get up at a decent hour, though).