One of the biggest flaws of TLOU is the lack of decisions for player to make INDEPENDENTLY. This alone breaks immersion and makes the game an on-rails experience with a couple of turns right and left at times.
The gameplay, as expected, is formulaic to the bare bones: enter a location - scavenge - kill people/infected - push a metal trashcan / bring a ladder / etc. - leave the location - cutscene - repeat. For approx. 13 hours of playtime, that makes it very repetitive and dirty.
There were some illogical scenes, too. For instance, Joel, the sniper covering Ellie, Sam and his brother from hostiles. You can fire as many shots as you like WITHOUT reloading. I randomly recalled the Saving Private Ryan church sniper scene - firing 7 shots with a Springfield without reloading. Come on.
Naughty Dog played the safe way - they didn't introduce any interesting and challenging puzzles, only pushing things from A to B. I was expecting something similar to HL 1/2 puzzles.
Also, Joel's companions in combat are useless and mostly annoying. Hostiles cannot spot them, kill them, or anything. You can't accidentally hit them, too.
I loved the characters, though. However, the story was weak - typical a teen will save the world, if you escort her to the right location fairy tale. I expected more information to be revealed about how the rest of world are dealing with the infected, etc. I especially disliked the quick skiptime quirks (Summer -> Autumn -> Winter, 20 years later etc.) without telling us ANYTHING. How am I supposed to care about my characters and their motivation, if they can easily settle down and survive for that long? That's bad story+gameplay design.
Voice-acting - one of the best I've ever seen. Too bad all the dialogs were mostly cliche-ruined. I mean - such voice talents deserve a better narrative.
TLOU poses too many questions and most of them are left unanswered. There's a sequel in the works, but that doesn't mean I forgive the devs for abandoning everything and choosing the worst ending - a cliffhanger. I expected at least 2 endings - as in Metro Last Light. Say, your actions throughout the entire game MUST mean something. For TLOU part, that was very lazy.
Technically, TLOU is a marvel. But it's core is a bit flawed and could've used some tweaking / improvements.