The most disappointing game I've ever played? I've taken a few minutes to consider that because I generally enjoy the games I pick to play, with some obviously being better than others. While I can't really put a finger on a specific game, perhaps I can pick a series? The most disappointing gaming series I've played was the Call of Duty one. I LOVECall of Duty, but only the ones to Black Ops II. I wouldn't play any others, especially after attempting the awful COD Infinite Warfare one.
I just like the old ones. I can't help it.
With that, maybe another game - the "new" Runescape (anything after 2007 update). While I did continue to play after Runescape took away the free in-game market, while also taking away or managing what a player drops while in the wilderness (wildy; a place to kill other players), I couldn't really get over the fact that they redid the graphics of the game. I loved the old graphics. I remember getting up incredibly early in the morning (or, staying up just as late at night) with friends playing Runescape before school. Now, with the new graphics? Sure, it looks "nicer", but I preferred the old graphics, the old barter system, the old Pking system, and everything else pre-2007. Yes, I know that R/S now has "Old Runescape" but now I'm just too busy anymore. *Sighs*