Driver 2 was a broken pile of garbage.

"Real Money Auctionhouse", and the mess they build around it called Diablo 3

Yes the first one was better in my opinion .

I forgot to mention Syndicate Wars, that was another huge disappointment. The first one was awesome, I loved that game, but the sequel was nothing like it, and they had to go with the horrible 3D graphics of those days.

Without doubt Mass Effect 2. It was utter, utter crap. But at least I learnt my lesson, and didn't waste time, effort and money on the third one -- or anything else those ghouls have made since.
That's a good shout. I love - totally loved - Mafia (1). Then the sequel came and it was a total letdown.

Since people aren't just talking about sequels... Civilization 5. Way to take a fantastic game and completely butcher and dumb it down. Yay!

Trine 3 as well. Loved the two first games, and then they fecked it all up.
What would this be, the credits? *confused*

I name just a few, otherwise i'd be sitting here all day:
Settlers 3 and everything afterward....what happened there? Instead of building of the greatness that was Settlers 2 it slowly turned into a mediocre RTS

Shock Troopers 2...you pay a couple hundred bucks thinking it would be as great as the first one, only to be disappointed by the "dumbing down" (No Team mode, less routes to chose), the ugly graphics and not so great controls and then you paid so much money for it....

Dragon Age 2. I love Origins but the second one is so extremely bad, dumbed down, badly written, idiotic that it's actually quite painful to play.

GTA San Andreas - It's a mess of broken, unfinished, never thought to the end ideas all in a setting you either love or hate, i hate all the rap and ghetto shit, so after the fantastic Vice City this was a gigantic disappointment.

EVERY Alex Kidd game after Miracle World with Shinobi World being the sole exception. I still can't wrap my mind around the fact that Sega went into all kinds of stupid ideas (BMX games) or just re-skinning some unrelated quiz game (Hi-Tech World) instead of giving the fans what they want: A sequel to one of the best and more innovative plattformer of the mid-80's.

And of course Bethesda raping the Fallout Franchise. It still hurts.

Metal Gear Solid series. I love the first one and enjoy second one in oil ship, after that it just got flop.
Metal Gear Solid V gameplay is better but storyline - what??? Future solider that was more advance than first Metal Gear?! Why add Aliens? Why Alien?!

I loved Mafia I and Mafia II. To me, they rate up there with some of the best genre storytelling in games. Now, Mafia III...

Mafia III is a mediocre story terribly told with broken shooter gameplay and a host of elements missing since Mafia II. I played the entire game hoping as every hour passed that it would get better. It didn't. If it weren't for the 60's setting and one of the best rock soundtracks in a game, I couldn't have finished the thing. And, I'll never touch it again... not even for the music.

2K really messed up when they disbanded 2K CZECH and gave this game to HANGAR 13. Big mistake.

Now, vying fwith Mafia III or my least favorite sequel would be DRAGON AGE: INQUISITION. Although I only played small portions of the earlier titles, I bought this on some many critics rating it in their top 10's that year. Wow. What a huge, bland, bloated world of fetch quests. It looked beautiful but was utterly boring and... by the end... actually angering. I've never played a game so big with so much monotonous, repetitive bloat that it sucks all enjoyment from the game; Mafia III was close, but DAI takes the trophy.

I don't remember being disappointed by many games, let alone sequels. The first that comes in my mind is Oblivion. I played a lot of it. Completed all the guilds' questlines, the Daedric quests, pretty much every other side quest. Then the main quest remained, I had only played a couple of quests there but I felt very bored and lost my interest. The world seemed so bland and typical high fantasy, especially compared to Morrowind. The dungeons are awful. Questing is mostly mediocre. Gameplay had some improvements but also some bad aspects. Yeah, I could call this disappointing.

Another one is Dead Space 3. I had fun with the game, it is good at what it does, which means if you are looking for an action packed horror game that relies on gore, then go play it. But sadly it strays far away from the previous two games and I consider it a definite step down.

I agree. But the sequel is quite ok as well... especially with this on top. Try it out with the mod if you haven't already - you won't regret it!

There is something between a start and an end. And often it's the biggest part. ;)

I have a feeling you would probably label it as "utter crap", too, but me, I enjoyed it.

I don't know if Final Fantasy Tactics Advance counts but I'll throw that out here.

Stronghold Crusaders 2
Don't have to say much else, if you don't know why I dislike it its best you play it yourself.
Man I loved Ultima 7, 8 was alright but a big step-down from the other games.

Diablo 3 is getting a Necromancer.

We may have to remove it from this list.

Necromancer? I hardly knew her!