Except Shadow of the Colossus had an ideal climbing mechanic that they could have moved wholesale to TLG, minus the stamina gage. In SotC the climbing feels organic; You need to hold a button in order to actually hold on, you weren't magnetized to a colossus' fur. This gave you a level of control over your climbing no other game has ever surpassed. In TLG you have to sluggishly traipse yourself across Trico, because the game locks you onto him as if you're covered in velcro. This makes it so that climbing Trico always feels like a chore, where you're constantly hammering the X button to try and detach yourself from him, because you can't simply let go or jump off him without the annoyance of the kid auto-locking back onto him.
The game also suffers from massive input lag, sometimes with buttons not responding initially when your on Trico. Petting Trico almost always requires a second press of the O button, because pressing and holding it once will often just not do anything. And then there's the giant button prompts which show up for every interaction with a switch, a barrel, a spear, anything, which you can't disable in the options. The controls never become organic or "invisible". And the camera is headache inducing, and not just when you're on Trico. The camera just moves awkwardly and slow. It's like you're playing a Souls game, but the camera is resting on a waterbed. And the combination of the kid's jerky-ass movement and the auto-stop near edges makes for some incredibly clucky maneuvering in tight spots, like high walkways, wooden beams, broken staircases.
Then there's the moments where the game makes you wait for shit to happen, like when you're trapped in the rolling cage or you're hanging from the branch by your collar. Or in the final sequence where it's supposed to be really exciting as you're (auto-)hanging onto another Trico flying around, but the whole sequence is entirely scripted with zero danger, and it goes on for way too long.
And speaking of that spoiler, the game pulls that way too many times as well. Like, how many times does that almost happen? Four times? And each time the game seems to milk it for all it's worth. 'Oh no, now it might REALLY bu true!' Yeah right.