Games that seemingly should have flopped? How about Deadly Premonition. The game is mechanically bad and has a really lack lustre story. And yet, it seems to have done fairly well for itself.

Hm... probably not deserved to flop since many people liked them but some where i dont really see why:

Diablo: Not really bad games, but the story was always weak (the lore kinda nice though), and Its clicking, nothing but clicking like a maniac, in the same environments for a thousand times.
i liked one and two but i never got how obsessed people became over 2.

Shadow of Mordor:
Played it for 4 hours and got totally bored with it, might be just me but i dont see the appeal.

Dead Space:
Didnt find it especially creepy (might have helped i guess) but the camera is annoying, the movement is annoying and so is the backtracking, like many other horror games its trying to "scare" the player with technical limitations, i never really liked that.

Minecraft:
Dont really see why people waste hundreds of hours building something ugly out of square blocks. Get Blender, its free and produces something actually aesthetically pleasing, probably in a smaller amount of time ;)

The Sims:
Taking the most annoying things about real life... and make a game out of it to fill that spare time? So boring ;)

Also all those annually updates series like CoD, sports games and so on, is there ever enough progress to warrant a new game? but well, people buy them.

Diablo 3.

It's a mediocre game that requires a degree in computer engineering to get a server for. XD

Yet people bought that piece of shit and they still do.

Seriously, they came out, offered a code that for $60 allowed you to rent a game which upon release, allowed you to log on at 3am and play for five minutes, IF YOU WERE LUCKY! :P

WTF!?

Deus Ex. Awful voice acting and music, dated graphics even for it's released date and awful controls.

In theory I'd agree, but:
- you have no in-game info about what is the intelligent choice. Basically any non-standard build is at risk, unless very well planned (luckly I noticed in time).
- ending up with a weak character after hours of playing is horrible (but even Diablo2 had this problem).

Brutal Legend... it straight up LIED to everyone... Great first part.. Shit RTS.. if they focused 100% on adventure hack-n-slash it would have been so much better IMO. I dont get the love it has :(

And you did not even mention the Auction House fiasco,proving that mixing in game auction functions with game money with buying thing with REAL money was in invitation to real problems..some of the legal.

A lot of Diablo fans think the much more modestly budgeted and hyped "Torchlight " games were vastly better games and had a much more "Diablo" feel to them then Diablo 3.
Of course, Torchlight being designed by members of the original Diablo team had something to do with that.
And the Torchlight team had learned their lesson with the fiasco of Hellgate:London:That ir is better to concentrate on doing a modest number of things well then trying to do a lot of things with mediocre results. They also learned about the dangers of hyping a game so much that you were guaranteed huge on line launch problems with the disasterous launch of Hellgate:London.

Spore. It had that EPIC creature creator. It should be impossible to screw this up. Yet, I can't mention a game that has worse gameplay.

SPORE did not exactly flop,but it did not sell nearly as well as expected, EA and Maxis were expecting Sim City and The Sims sale figures, and it did not happen.

Assassin's Creed III: Political Correctness Gone Mad. In spite of the... less-than-favorable opinion it holds among longtime AC fans to this day, myself included, not only did it not fail in the market but it's actually the series' best-selling installment to date. Wut.

And on a completely separate note, Recettear. It's a brilliant game, don't get me wrong, but it's so... japanese, and coming out back when hostility towards japanese games was much higher than it is now, with a price-tag that wasn't high but wasn't bargain-bin either, I doubt many people expected it to succeed, let alone as much as it did.

World of Warcraft.

It seems to be built on the back bone of a series of terrible game mechanics.

The kill locking mechanic that effectively punishes you for helping people. I know it was removed recently but that doesn't undo the damage of teaching people the correct way to play is to be selfish.

The one unique name requirement. World of Warcraft is an online entertainment service that is designed to support hundreds to thousands of people at one time, they promised not to delete accounts, they promised not to delete characters, you can have up to 10 characters per server, and most probably have at least two. That's hundreds of names that are off limits to you. Why do this to a customer that bought the game and agreed to a $15 a month subscription fee? Why stop your customer from playing because of something this meaningless?

The round robin mechanic. Its the one with the need and greed buttons. Its also an honor system on the internet that is easily exploited for personal gain (loot ninja) and easily used to piss other people off (jerk, troll, etc).

Having a difficult time coming up with anything. For one, I don't have the extensive market-wide knowledge and exposure of a lot of other players. But second, whenever I think I have one figured out I think to myself, "But it's a product of its time". Thus Dungeon Siege might look meh to me today, but I had a lot of fun with it when it was new.

Why does a game deserve to "flop" just because I might not personally like it?

This seems like a hate thread. I want Blizzard to burn, so there you have my list of games that should have flopped. (Yes, I like Starcraft and Diablo, but I still hate Blizzard).