Good games under 4 hours long

Doc Clock: The Toasted Sandwich of Time (2-3h)
Hotline Miami
Osmos (but one level is imposibbru so u can try to beat it for more than 4h...)
Rotastic
The Ship SP (2h, it's really a good game, they should do SP longer :/ )
Wizorb (2h)

Portal, at max four hours.

I finished nightsky in less the 3 hours, portal 1 isn't long too and maybe foreign legion: buckets of blood which is a short game but relly good.

DLC quest became my fav!
another game to add on this list is Evoland.
great story etc but it sucks that it's so short.

Machinarium (5-6h)
Papo & Yo (4h)
both great games

Bastion is one of my favourite games. Nice story and high replayability

Binding of isaac? :)

the half life add-ons are about 5 hours long iirc..and episode 2 is also bvery short but great :D

I'm playing Tiny and Big right now and it is awesome. According to HLTB it should take you ~2.5-3h to beat, though I'm fucking around collecting achievements in first two levels instead of carrying on. Anyway, this game is good!

NightSky - get this definitely, a real gem.

And Yet It Moves was an entertaining game as well.

Also Blackwell series (played only Legacy, 2.9 h, used walkthrough once, cause of game not being consequent).

From point n clicks - free Ben There, Dan That! - funny as fuck. Surprisingly, paid sequel, although longer, was worse. Kaptain Brawe was alright, nothing special. Puzzle Agent was pretty good. I beat all of them under 4 hours.

Probably the only one that hasn't been mentioned already: Shelter.

...and Modern Warfare's campaign evil grin

• Braid (hours needed depends on you but the game can be completed in less than 1)
• Ion Assault (started playing it for cards but it revelaed an interesting game)
• The Path (better to play in small sips)

Eversion.

From the main list, I would take out "eXceed" (which is a good game, but feels unfinished), and would replace it with "eXceed 2" & "eXceed 3", which are much, much better in comparison (1-1.5 hours each).

I would also add "Home". Great little game, with a good story (1 hour).

"Super House Of Dead Ninjas" (1-2 hours, to get the "real" ending).

"Dear Esther" (2 hours).

Gone Home. Amazing game. Finished in around 3 hours (maybe a bit less). The kind of game you really should play through in one sitting aswell.

I trought The Darkness 2 was around 4hrs, right?

add Fortix.

Sorry, but I have to say: McPixel on a GOOD game list? :P

Dark Souls

Papo & Yo - it took me about 4 hours to beat it and I do not regret it. Great, engaging and enigmatic storyline with nice, but not best gameplay. This game is underestimated even with metascore at about 70/100, which is not bad but it deserves a lot more.

Mine VVVVVV with 2.5 hours
and braid full achievemnets with just 3.5 hours

Leisure suit larry reloaded

Samorost 2

Cave Story + can be finished in 4ish hours although it can take double of that too.
Jamestown should be well below 4 hours, possibly Sine Mora too.
Superbrothers, and most likely Shank too.

Portal. Popped it a couple days ago and was surprised when I finished it a little over an hour later.

Nice topic. My additions:
Papers, Please (Any% run can be done in 4h)
Binding of Isaac (You can do a first full run in under 4h...if you're not bad at this type of games ;)
Hotline Miami (again, under 4h if you're not bad)
Portal (this one is easily under 4h, speed runs take <30min :P )
Little Inferno
Hammerfight (if you won't have too many technical problems you should finish the game in ~3h)
Splice (great puzzler, should be under 4h if you're a genius ;) )
Super Hexagon (I'm yet to get any clear/achievement in this one but probably it can be done in under 4h of practice)

P.S. Also bobofatt, how about giving someone rights to update the list in OP? It would be nice to have such list for those of us who crave some quick backlog completion ;)