I beat Shadow a few days ago actually and thought it was pretty middling. A gorgeous, but pretty mediocre game.
I was a fan of the first game of this trilogy, but this one just didn't feel all that great to play. The platforming and puzzle solving super simple and repetitive (the same "uh oh, the ledge is crumbling!" "uh oh, a slope!" "oh no, the wall is crumbling!")
I did most of the optional tombs and thought they were pretty basic too. Only one short part of the game impressed me, it was the big spinning death cylinder that you climb up. It was a large platforming puzzle section that actually required you to look around and figure things out a tiny bit.
Sadly that was pretty much the only part that was that memorable.
I liked the combat in the first Tomb Raider reboot game, but felt like it hasn't been as good in with Rise or Shadow. There wasn't much combat or stealth in Shadow, but what was there was pretty basic and just felt lacking some punch.
The whole Trinity storyline that continues from Rises is just stupid, but it was never good to begin with so I wasn't even playing for the story.
I did laugh during a ridiculous combat moment when some evil henchman who I had completely forgotten about (I think they were in RotTR) pops up and starts taunting me. It was like "Hey Lara! Remember me! I'm gonna kill you!" and I had no idea of who they were, haha.
If nothing else, this game did make me want to go back and replay the first game in this reboot series, as well as Tomb Raider Anniversary which I also reinstalled. I love the platforming and puzzle solving in that game, I remember the levels being huge and so satisfying to finally solve.