Deleted

The Vanishing of Ethan Carter.

I usually get bored easily with sp games. I enjoy more short games, so much that before starting a sp game i check the lenght. If it's too long (like 20 hours or more) it's not motivating.
Many games i enjoyed have been named already.
I read some comment and i didnt see Spec Ops the line. Great game.

My favorite category. :) I love short indies. xD

Definitely try most of these if you haven't : (too much puzzle stuff, I know)

Limbo, To the Moon, Gemini Rue, Portal, Thomas Was Alone, Rogue Legacy (may take more, but short runs are always very fun and rewarding), Tengami, Shadowruns, Unmechanical, Type Rider, Inner World, The Dream Machine, Trine, Ittle Dew, Back to Bed

Singularity

http://www.steamgifts.com/discussion/zvGVU/short-games-recommendations

• To The Moon
• Braid
• Bastion
• Transistor
• Undertale
• The Stanley Parable
• The Beginner's Guide

Try The Swapper if you like puzzle platformers. It's pretty short, kinda reminds me of Limbo because of its moody atmosphere and overall feeling of loneliness you get while playing it. And the music is superb.

I see so many games in the thread which took me 20 and more hours to complete, and they all considered as 'short games'.
I might play them wrong =<

Batman: Arkham Asylum.
My favourite of the recent Batman games, is short (I basically finished the whole thing in two or three sessions during a free weekend a couple years ago), the gameplay is fun, and it doesn't overstay its welcome with idiotic open-world fetch quests and collectable things.

I see that no one mentioned Spec Ops: The Line yet.
sumbit comment

Am trying to think of something that hasn't been already mentioned. Let's see...

Anodyne (Oldschool top-down action-adventure with influences from Link's Awakening, Yume Nikki, and Earthbound)
Freedom Fall (Vertical platformer with a short branching story and quirky humor)
To Be or Not to Be (Hilarous choose-your-own-adventure by the Dinosaur Comics creator)

Far Cry 4 less than 20 mins

Out there somewhere is really short, but very much worth getting all the same.

Hotline Miami

I enjoyed Papa & Yo quite a bit.

There's a really short free game from the creators of Stanley Parable called Dr. Langeskov, The Tiger, and The Terribly Cursed Emerald: A Whirlwind Heist which I played recently and definitely can recommend.
Also I don't now if you're into such a games, but most hidden objects games are pretty short, like 2-4 hours.

The darkness 2

Looking through your list of owned games:
The campaigns for the original Dawn of War is surprisingly short.
Orcs must Die is ~6h
LOOM is a short adventure game (though being an adventure game, exactly how short depends a lot on you.
Same with The Dig (It's also one of the best point & click adventure games I've ever played)
Duke Nukem 1 & 2 are two short 2d platformers.
Shank, just over 3h

Medal of Honor. I finished the game in about 7 hours.

Best story i`ve seen in 6-7 hours - Spec Ops: The Line.
And +1 to The Darkness II

I prefer fairly short games. I recommend Sniper Ghost Warrior 1&2.

I'll list some with links to Steam store so you can check them out:

• Mysterious Eldritch
• So innocent Eversion
• Atmosphreric Deadlight
• Ridiculous McPixel
• Legendary Papers, please
• Contagious Plague Inc, Evolved (Hard to say what is playthrough with this one but I'd say that this is short game :) )
• Sandy SteamWorld Dig

Then there is always the non-Steam game Muddy Heights.

Both Amnesia games (the first is about six hours and has lots puzzles, the second is about three hours and drops the puzzles but ups the story so its really down to whether you like puzzlers or walking sims)

SOMA (about nine hours, amazing achievement in design and storytelling, terrifying in a more subtle way rather than LOLJUMPSCARE, and honestly my GOTY 2015)

Zeno Clash (about three hours, weirdest brawler ever, only game i've played where the crap voice acting improved the game)

The Last Tinker: City of Colors (about six or seven hours, bright and colorful, nice story, fave game ever right here)

Anna's Quest. In Daedalic Entertainment we trust! The storyline is so amazing. The game's duration depends on your ability to solve riddles.