The longest game you've beaten start-to-finish in one sitting.

[Malkavian]

Lets see....

Alan Wake (360)
Batman: Arkham Asylum (ps3)
Modern Warfare 2 (ps3)
Tai-FU: Wrath of the Tiger (ps1)
Metal Gear Solid (ps1)
Silent Hill (ps1)
Silent Hill 2 (ps2)
Donkey Kong Country (gb)
Super Mario Land (gb)
Bioshock 2 (ps3)
Portal (pc)
Resident Evil 4 (ps2)
Resident Evil 5 (ps3)

I think thats all the games I've completed in one sitting, but which one took the longest, I cant remember.

 

[Nalgas D. Lemur]

I finished Just Cause 2 up to 54% in a single sitting. It doesn't sound much but...Just Cause 2 is HUGE!

How in the crap did you do that? I can't fire it up now to check, but I think I was at around 15% after ~25 hours last time I played.

 

[TheTaco007]

Well I've only ever beaten one game in one sitting, (well, besides Portal) and that was because it was incredibly short.

So.... Halo 3: ODST in 3 hours and 45 minutes on heroic, my first time playing it.
I was kind of disappointed by how short it was.

 

[Captain-Giggles]

I remember when I finished Mario 64 DS I thought "Wonder how fast I can do it?" so I started a new game and 7 hours later at 4 in the morning, all 120 stars. I slept well that night.

 

[Jman1236]

The magical quest starring Mickey Mouse, but I don't think it counts since there is no save function.

 

[MARKMCMARCUS]

MW1, Arkham Asylum, can't think of any others at the moment.

 

[Gabanuka]

Mass effect 1 and 2. Did it for charity and raized 700 quid.

 

[sid02]

The first Devil May Cry. I had a friend over and I wanted to show him the game so I played through it start to finish in 4-5 hours.
It was an awesome day to be a video gamer ^^

 

[Chechosaurus]

Halo: Reach

Five of us went to the midnight launch and played it through on Legendary co-op. We split into two groups, moved all of our TVs and 360s into the living room and spent about 10 hours playing it until we had all finished it. I think that we could have done it in about 8 hours but one group ran into a massive glitch and had to restart the last level and after about 5am we were all so tired that we became pretty incompetent with the DMR which slowed us down a fair bit.

 

[beniki]

Medieval Total War 2. Took my German's and rampaged across Europe, taking the whole map before my first Emperor died, with a real time of just over 5 hours.

Remember kids, creative tactics means your under sized army of crossbow and spear men can take over the world. And don't skimp on the mercenaries.

 

[mrF00bar]

Rome: Total War took me about 5 hours to infect the hole map lol.

Only FPS I can think of is Half Life 2 + Episodes 1 & 2 in one sitting. FREEMAN HAS NO WEPON.

 

[Lord Kodous]

Portal
all the Halo's
Star Wars: Republic Commando
maybe a few others, I can't think of anymore though

 

[supermariner]

I would break my previous record, standing since 1998, of 33 straight hours (a Final Fantasy VII run from the Midgar train station to Sephiroth's inglorious demise at the hands of the Knights of the Round, and yes, I managed to shoehorn the Chocobo sidequest into that fast a playthrough

it is impossible for me to respect you any more than i currently do
well played sir!

as for me it's probably 100%ing Spyro 2
took me an entire sunday, but i got all 64 orbs and all the treasure

 

[katsumoto03]

All the CoD and Halo games, Fable 3, Assassin's Creed 1,2,Brotherhood, Portal, Mass Effect 2 and a few more that I probably can't remember.

 

[CharrHearted]

heavy rain - 10 hours...My gawd!

 

[Enemy Of The State]

Fullmetal Alchemist: Dual Sympathy, I beat it in the time it took for my food to arrive at a restaurant.
Modern Warfare 2 campagn in one evening.
Call of Duty: Black Ops campaign in one evening.

 

[Zeraki]

I used to be able to beat Ocarina of Time in one sitting, since I had the entire thing memorized I could usually just steamroll through the game. The only thing I ever had a problem with was the freaking water temple, there was always something in there that I would forget about and get hung up on.

 

[Professor James]

The only game I beaten from start to finish in one sitting is Super Mario Bros. Although I almost beat RE5 in one sitting, made it all the way to chapter 5-2

 

[Cuppa Tetleys]

I beat Halo 3 in one sitting on heroic on my second playthrough

 

[FallenTraveler]

uhm, never, I dont think... maybe a couple psp games, maybe Daxter, MAYBE... but other than that I dont have enough "lazy time" to play games for a marathon session, usually there is some annoyance that breaks my fun times... that and I like to space it out to get the most out of 50 dollar games

Edit: RE5, me and my friend played online co-op from start to finish in one afternoon into night (about 3-11) that was fun.