I've never played any of the original Half-Life games - they were before my time. Or more accurately, I was playing PS1 Shrek when the original game came out.
I really liked the world and setting introduced in this game, but the game is definitely way too fucking long. Levels just go on forever. There are like 19 levels and each one besides the final one must have taken me over an hour to complete. For a purely FPS game with no other gimmicks or RPG levelling system, that is frankly exhausting. And there was a point on Xen - during the conveyor belt section - where I was actually losing my fucking mind because of how unfun the game had become, throwing endless waves of tough enemies at you while you struggle with ammo scarcity.
It was a far cry from the beginning of the game where you're exploring the darkness and destruction of Black Mesa, twitching every time you see a headcrab or zombie.
I will continue this into Half-Life 2 for sure, but I was not sold on this world from this game alone.

Ubisoft is great at creating really addictive gameplay loops, but their storytelling has been lacking as of late.
A bunch of inconsequential side characters litter this story, with little interaction with any of them, so any deaths and twists in the story do not hit at all. The automatic story missions are also a pain in the ass, especially because it locks you out of acquiring some of the story missions in the game. This is really annoying from someone who is a hardcore side quest completionist, making it so that my playstyle of clearing out the entire map was actually detrimental to my experience with the story.
Overall although - story issues aside - this is still a fun game to just play and get lost in. It's beautiful, it's fun to play and it's packed with things to do and discover.