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.
Original deus ex. Yeah I’m sure the story is very good. But gameplay is just not enjoyable to me no matter how many times I try. Combat is annoying unless you put all skill points to X gun skill, then it is boring. In stealth I have no feel how visible I am and gep gun is annoying to use.
I have tried to enjoy it at least 5 times since I like the new ones but at this point I give up. And yeah I tried with mods and shit.