I've been trying to think of ways to encourage users to log their completion times, but I figured I'd start with something that doesn't require any development time :)

I thought it might be fun if we all posted games that we enjoyed that are fairly short games (I'm starting with < 5 hours). I've tried to create a list with readily accessible games and I've tried to avoid bigger games that everyone already knows about. I'm always looking to squeeze more games in, so short games work out great for me. If you have any games you'd like to add, post 'em up!

Oh and as a side-note, if you haven't seen it yet, there's a "quick filter" on your Collection page that lets you quickly find the shortest games you haven't finished yet. The more completions we enter though, the more accurate and dependable that filter becomes!

• Kung Fu - This NES game is super short, I finished it in 18 minutes a year ago. I played the heck out of it as a kid, so I knew it pretty well, but it's still really short. And that 18 minutes required me to restart a few times too, so yeah, it's really short!
• Thirty Flights of Loving - This is a weird....game, but it's super short if you're just rolling through it. My completion is for 20 minutes.
• Spoiler Alert - I was pleasantly surprised with this game. It's an hour or so long and that includes getting all of the achievements. It's only $3, but I think I have an extra key too, if someone promises they'll enter a completion for it :P
• Felony 11-79 - This is a fun PS1 game, but it doesn't have a ton of content. It's not terribly expensive, but I don't think it's had a digital release, so you'd have to track a copy down somewhere.
• Rez - This game always seems to be overlooked, but it's fantastic. It's a tough game, but oh-so-addictive! The PS2 version used to be kind of expensive, but I think it's still available on Xbox Live for a lot less. Speaking of which, I should try that version out! A single playthrough is about an hour or two, depending on if you fail any stages. The sequel-ish Child of Eden is also pretty good and last time I checked, it's dirt cheap on Amazon.
• Zoom! - I had never heard of this game until earlier this year. I'm not even sure how I stumbled upon it, but I'm glad I did. It's basically just Qix, but it's a nice clone. I used my Retron 5 and abused save states to plow through it in a little over an hour.
• Beast Boxing Turbo - If you like the old Punch Out games, you should give this one a shot. It's not nearly as good as those, but it's an enjoyable boxing game that won't take you very long to play.
• Gun Metal - I remember being interested in this game when it was on Xbox and had no idea it was ported to PC until I bought it on Steam a year or two ago. It's a "blow everything up" kinda game and I'm okay with that. I think I have a key for this one too, if anyone wants to blow some stuff up!
• Hexcells - This is a great logic puzzle game and we actually have quite a few completion times entered for it, but the more the merrier!
• Titan Attacks - This is a very enjoyable Space Invaders clone. It's another one that I tried somewhat randomly and was pleasantly surprised.
• The Guardian Legend - Well, of course I'm going to include this game! It's a tough game, but you have unlimited continues and it's somewhat non-linear, so you can try different levels as your skills improve. I'm able to finish it in under 3 hours, but I've beaten it countless times, so it might require a little more time for you first playthrough. I don't think it's particularly rare, so you should be able to track down a cartridge pretty easily (and cheaply).
• Chasm: The Rift - This is a budget FPS from the 90s that's pretty much just Quake with horribly cheesy cutscenes. It's a few hours worth of old school shooting action. It's nothing special, but if you're into the niche, you could do worse.
• Thomas Was Alone - This is another game that we several completions for, but it's so good, I needed to include it. A total of 203 users own it, so if you're one of them, carve out 3-4 hours and BEAT IT!
• Toybox Turbos - Did you like the old Micro Machines games? If so, you should pick this one up when it's on sale. I had a lot of fun with it, but I rolled through all of the content and unlocked all achievements in just a tad over 3 hours.
• Pikmin - I've played through this game so many times on both GameCube and Wii. It's a very unique console game / series that somehow keeps getting overlooked. If you have either of those systems, track it down and play it!
• Jet Set Radio - This was one of my favorite Dreamcast games and the Steam port is pretty decent. It can be tough at times, but highly enjoyable throughout.
• Nights into Dreams... - Ah, so much nostalgia here! I played this one a lot in high school and it's still really fun to play.
• Meltdown - Okay, this one took me 7 hours, so it's over my self-imposed 5 hour limit. But that's only because I did a ton of grinding kept playing well after I "beat" it. Yet another indie game I was pleasantly surprised with.
• Giants: Citizen Kabuto - Okay, okay, another one that's more than 5 hours. But this one is sooo goood! If you haven't played this yet, get yourself over to GOG and pick it up now (especially since it might be on sale)!

And look at that, Giants is on sale for the finale ;)

I played through Giants: Citizen Kabuto many years ago and remember having a really good time with it. Granted, anything that lets me run around as a giant monster gets my two thumbs up generally.

My short list of recommendations:
- Cave Story - Great solo-effort created game that's been ported across a number of platforms since it's initial release, very metroidvania-ish, but with guns, robots, and rabbit things.
- Little Inferno - One of those "sort of a game" games, but it's pretty short and if you're a pyromaniac who likes incinerating everything, right up your alley. Interesting background/setting I wish they'd done more with.
- Puzzle Agent 1 and 2 - If you like adventure games, puzzles, and the setting of Fargo, here you go! (No wood-chippers though)
- Antichamber Speaking of puzzles, this game is does some interesting things with perception and shifting environments.

Installing Cave Story and Little Inferno now! I briefly played Antichamber and it seemed neat, but then I completely forgot about it. I've considered Puzzle Agent during various Steam sales, but wasn't quite sure about it. If it reminds of Fargo though, I might have to indulge (even without wood-chippers). Are those games kinda like the Professor Layton games ?

Yeah, I would say it's a pretty decent comparison to Prof Layton styled games, though with a bit more interactivity outside of the puzzle solving. Don't play them back to back however, like I did, as there's a bit of repetition in puzzle types in the second taken from the first and it'll be a bit disappointing if you're big on the puzzle element. Give them some breathing room apart, haha.

I just finished The Swapper again and it took right at 6 hours. So not under the 5 hour mark like you asked but still a pretty good game that is relatively short.

@dhobo - Great recommendation with Little Inferno! I see now what you mean by "sort of a game" and I really thought it was more of a game, but that's okay, it's pretty fun!