How long should games last?

It really depends on the kind of game. A game like Heavy Rain was fine at 6-8 hours, but Final Fantasy XIII should be 50+. I just don't think you can make a that big of a generalization when it comes to the length of a game.

20 -30 hours 
 
Edit: But yeah, depends on the game.

I have to agree that it depends on the game. I thought Portal was the perfect video game playing experience at five hours or whatever. If Deadly Premonition had been five or ten hours, I would have been pissed. It all kinda depends.

10-40 hours so that the game is worth how ever much your paying for it.

  The reason I ask this question is because I personally do like games to last fairly long. It's always a bummer when my favorite games just end and all the options I have is just playing it again. 
 
 
  I realize that there has to be some sort of conclusion for the player to feel like they have accomplished something, but that can be realized by planning a story with this kind of "milestones" that could be story or gameplay driven. 
 
 With all due respect to reviewers, Sometimes I feel like how long a game lasts it's very dependent on their opinion and how realistic is the time frame to review those games.  But I wonder if vocal games are just agreeing with them because it seems like the norm.... 
 
 
 After all, the most popular games out there are the ones that last as long as you have interest in them ( I mean multiplayer and MMOs) And DLC it's becoming critical to the ones who love their particular games...People seem to want more. 
 
 
 
  Anyways, thanks for reading. I'm not American, so I apologize for destroying your language by trying to use it :).

I came from a time when single player games that weren't RPG's lasted for much more than 30 hours. 

The least should be 8-10 hours+ with enough depth for multiple play throughs, with balanced difficulty modes. Single player games I enjoy usually last me 40hours+ even when a single play through on normal is only around 10hrs. Adventure/RPG games which are not combat heavy I expect good exploration and scale that should last me 20hours+, story focused games with massive cutscenes and dialogues I'd expect 50hours (since a lot of them went to running around and absorbing the world around you). 

It depend how the content and depth is spread. An 10hrs long game doesn't mean I could digest them in one 10hr session, I possibly can't even learn the entire combat system in 1 or 2 runs. a 40hr game with a big sandbox doesn't mean it has enough depth to keep me interested if the gameplay is stinky press a button to win and run around the same city collecting stamps or some shit.

none of those. I think for most games 15-25 hours is a good length. That's a good length cause any shorter and it's not really getting your money's worth and any longer and it can start to get boring. There are obviously exceptions, some games can get away with being shorter or longer than that, but in general 15-20.

I don't think it matters, it depend on the quality of the experience. Mass Effect 2 lasted quite a long time, whereas Uncharted 2 lasted less than half of that, but I can totally compare them both as gaming experiences.
If you're talking about a money-lenth ratio, then I guess somewhere around 15-20 hours is the sweet spot. Anything over could be pretentious *some exceptions*

Depends on the genre, 8-10 hours are good for single player games. Rpg games is good at 40 hours or more.

8-10 hours is the sweet spot. Why the fuck did Final fantasy 13 need to be 50 hours long, there's literally no reason for it with a paper thin story like that.

I remember on the bombcast the guys saying 6-8 hours is enough for a single player game. What a joke, I hate the way casual gaming is taking over, in in journalism. A game should be as long as possible in my opinion. If the sp is short (6-8 hours) and if it's a full price game than it should have a decent multiplayer mode aswell

I want it to last as long as I can handle it. Nice and sweet, or tough and long, it's all good to me. 
 
 
Wait, what were we talking about again?

Quite frankly, as long as the singleplayer of a game lasts 10 quality hours, it was worth the price of admission.

I realise that this has been said alot, but it depends ont he game.
 
I have put alot of thought into this, and In general I prefer my games shorter. Usually if a game is over 10 hours you start to run into padding (not all games are like this mind). However some games (read: Bethesda games) benefit from their length, because the goal is to give you a huge world to explore. So this is an unanswerable question, but in general the more the game focuses on a specific story or gameplay mechanic, the closer to 6-8 hours it should be.
 
But then I'm working on a text adventure that is very dense, and  I am only aiming for it to be 2-4 hours. Because I don't think the story will last longer than that without degrading in quality.

14 hours minimum 50 hours maximum 

If a game is really good for 10 hours then that is good enough for me.

4-6, because then i might finish it.

It really depends on the kind of game. I don't want an RPG to be longer than 30 or so hours, shooters I get bored after 20, and a lot of other games don't matter due to their multiplayer, or pickup games, like in sports or strategy titles. 

Completely depends on what it is you're playing.
 
When I start playing something like Final Fantasy I expect it to last at least 30 hours+, but I wouldn't want that from a Modern Warfare. I was thinking about this pretty recently, as I finished Heavy Rain and although I can't say for certain how long it took, it seemed to finish at the perfect time. Although I wanted more, I felt that where it ended was perfect. Going on for too much longer would probably have burnt me out. However, with the way that game is built you can go back and play the game again, getting completely different results from the different options. Obviously, if that game didn't have as many forks in the road then I might expect a little bit more for my money.
 
If I think about it, I am struggling to think of a game in recent history that finished, in my opinion, abruptly. So the game devs seem to be nailing this aspect.

I like long games. I think it depends on how you look at it though. 
 
Most FPS games have a short story because the main draw is multiplayer, so it's hard to judge. The same could be said about RPGs. Sure their story is longer in almost all cases, but most can be finished quickly if you only follow the story. What adds so many hours to RPGs are the side quests, collecting the best equipment, and leveling up/gaining all skills.
 
But either way, I say the longer the better.

None of the above: it totally depends upon the game. For example, Bejewled 2 on my iPhone: as many shits as possible. Mass Effect 2: perfect. God of War 3: close to perfect, would like some worthwhile DLC though.
 
I could go on. And on.

10 to 15 hours is great, but if I really love the game I'll play it multiple times.

Games should last as long as they need to. They should neither be dragged on by filler nor cut short by release dates.

i think that the games should be like 12 hours +. the game has to be a great game not some crappy game.

As many have said already it depends on the game. For RPGs and sand-box type games, twenty to thirty hours is a good number (for the main campaign) while for shooters and action games, eight to twelve hours is a good number. I wouldn't want a shooter that lasts thirty hours (would probably get too repetitive) in the same sense that I would't want a good RPG that only lasted eight hours (probably not enough time to develop a good story or proper character progression).

I don't want Gears 3 to be 40 hours, but I don't want Fallout: New Vegas to only last 8 hours.

As long as it takes to enjoy them. Some games like Portal are short but sweet, other games like Jade Empire are long and boring (by today's standards anyway). Developers should shoot for a clean-cut, polished game rather than one with a bunch of tacked on content, or just really stringy main content.

Depends on genre, like everybody else said. I don't wanna play a STALKER in less than 45 hours, but I don't wanna spend more than 6 hours to finish a Sam and Max episode.

I'd like games to last last more than a week, that means more than 5 sittings of 5 hours.  So about 25 hours.      I get disappointed beating games in one sitting.

There is so much wrong with this poll.
 
The only answer is:
 

No longer than they have to

I would say it very much depends on the game, but generally speaking 15-20 hours is pretty much spot on for me.

Depends on the type of game.  An action game being around 8-10 hours is just fine for me.  I would expect an RPG or an open world game to be at least 20-30 hours of playtime.  Any longer than that an it's likely I will never finish the game.  I'm looking at you, FFXIII.

RPGs need to be between 40 to 200 hours.  40 for the main plot, but up to 200 with all the minor stuff.  Action and Shooters should be around 12 - 14 hours.