as of yet i know none but i'm pretty sure that some people do know some games like this

Mercs 2 is janky as hell

I played Deus Ex one but not the sequel a lot of people seem to not like it.

Final Fantasy has some great games and some terrible sequels I guess.

Final Fantasy Tactics Advance

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Mercs 2 is janky as hell

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 Age of Empires 2.

Halo 2  
 
maybe not terrible but a serious let down compared to the first game.

Devil May Cry 2 comes to mind.

HAWK 2, from what i've played is god aweful.

 Nice to see a post that has nothing to do with the subscription fee for once. 
 
With that said, I'd like to nominate God of War II. It's not a terrible game by any means (it's damn right good at parts) but playing through the game had to be one of the most frustrating, excruciating experiences I've ever had with a game. For every one or two cool boss battles we get lame, boring puzzles and needlessly frustrating action sequences where if you fuck up OH WELL START OVER AT THE BEGINNING AGAIN! The story's horrendous and Kratos went from an awesome, actually somewhat likable anti-hero from the first game to a boring plot device who kills anything in his way (or fucks anything in his way that he hasn't killed yet...then kills them anyway).  
 
Such a huge disappointment, because the first game is one of the best action games I've ever played. The second one basically made me not want to touch anything God of War related, ever again.    

Mafia 2.

Super Mario Bros. The "real" SMB2 (aka the Lost Levels) is fucking terrible. One of the least fun games ever.