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.
I haven’t liked a Need for Speed game since the original Most Wanted (and that was the first one since Porsche Unleashed.) I’ve played a few since and some were okay, but none of them have grabbed me the way the old NFS games did. I spent more time playing any of the first five NFS games individually than I have playing all of them in total since MW.