when one game is hailed as the "savior" of its series, you as a fan have high hopes and cant wait to play it then you end up being very dissapointed.

I know how it feels

Yeah, while I wouldn't call it one of my most disappointing, it was a bit of a letdown compared to the first one and how epic the trailers made it look.

I liked X & Y but that was because I wasn't expecting that much from it. I was expecting more or less the same thing but I ended up liking it more than I thought I would! 

Not gonna lie, I still haven't started Xenoblade 2 yet.

Even though I bought a copy, I'm still cleaning my backlog a bit before I start it so I don't have a bunch of games that I have to get to, and after XCX, it still sorta left a sour taste in my mouth.

XCX is far from a bad game, but I made the mistake of setting my expectations too high after the amazing story of the first Xenoblade.

Star Fox Adventures: a Zelda-esque adventure that unfortunately lacked the magic that makes Zelda games so good.

Star Fox Zero: ruined by stupid control mechanics and some new ships and vehicles that just made the game annoying as hell.

Metroid: Other M: the game is fun to play but the upgrade system is fubar. "You're authorised to use blah blah". Ugh...

Kid Icarus Uprising: I liked the humour and the flying segments but those ground parts made my hands move in ways they really shouldn't.

Paper Mario: Sticker Star is without a doubt. I loved every Paper Mario before that, and I'll defend Super Super Mario until I day, so playing it and slowly coming to terms with how awful it is was a painful experience. The creative decisions on display are so bad I'm baffled as to how they ended up in a professional, polished game. I despise Color Splash for similar reasons but from the moment it was revealed I knew it would be garbage.

Mario Party became bad after 7 but I never cared much for Mario Party.

I love SFA as well! I know it sounds contradicting but that's because I wasn't expecting the game to be 99% a watered down Zelda clone with a rushed and unsatisfying ending. Still I have fond memories playing it, the graphics are breathtaking with a good story and memorable characters but the game would have been so much better had it stayed as Dinosaur Planet.

Yeah the lack of a compelling story was my main gripe with XCX also.

XBC2 is much more like the first game, thankfully.

Super Smash Bros. Wii
Metroid Other M
Kid Icarus Uprising

Metroid Other M, Fire Emblem Warriors and Tokyo Mirage Sessions is what comes to mind, Warriors more about roster. TMS also the roster of Performas and how bored I was with the writing and characters

Usually I have a spot on idea of my expectations with games, some surpass it and some stay in the line.