Prototype Franchise: After the first game, the killed Alex Mercer and turned him into a second Albert Wesker. They also completly butchered the lore, introduced one of worst characters I have ever played as and made the game easy enough for everyone to play it.
Breath of Fire: Capcom has been ignoring BoF for many years, before they announced BoF 6, which is a grindy, pointless game on a app store. They have never released BoF 4 in europe and only recently BoF 3 got introduced in USA.
Dota 2: I have played this game since beta and it has been getting worse with each and every patch. At this point a guy can't play this game without a party of 4, otherwise he risks losing his sanity. Nobody even tries to become better, russians are everywhere, cosmetics are everywhere, etc. Only Dota 1 lives, but even then not many people play it anymore.
Singularity: The game had a potential, but it was never fully realized and then it was forgotten.
Bioshock: First game was amazing, second one was even better but the last one was just good. Wish there was more to Rapture and big daddies.
I guess those are the games I hat a lot of fun with, except Fallout.