Personally there are a few games which left me very dissappointed, after hyping myself up for years in certain cases.
Divinity Original Sin: turns out I prefer more streamlined, less packed games (love Pillars of Eternity) and that coop play in a CRPG stresses me out.
Wasteland 2: I actually managed to finish this one but secretly I admit I was hoping for a better Fallout which I didn’t really get. New Vegas did the cowboy theme much better.
INSIDE: while the design was cool, it was just a ton of boring, easy puzzles in comparison to LIMBO, its predecessor.
Halo is one of my favorite games of all time, and I played the shit out of the first one when it came out. It was absolutely game changing for console shooters. Before that, I hada SNES (skipped N64 era). It absolutely blew my mind.
Unfortunately, I don’t think it really held up. If you played it back then, the nostalgia still hits hard and that’s fun. But if you play it for the first time now, it just won’t hit the same, unfortunately.
Having just played through the MCC recently the first halo is a bit dated, but 2 and 3 are some great campaigns. Reach and odst have decent stories, but the campaign is more average. The biggest surprise to me was how much worse 4 is than I remember. I knew it was disappointing, but playing it back to back with the others really makes it obvious.
I had played all the games before though.