Omega Boost. Can beat it in about an hour or two. Not get all of the secrets and stuff, but just play through the game normally. Its fun as hell though...I've beaten it many many times.

The .hack games are short too, though if you treat all four as one game then its kinda long.

Gungrave on the PS2 is pretty short... I think I finished in under 2 hours on my first play through.

Final Fantasy viii- finished it within a day

the shortest game i played was p.n.03 it was an hour and a half long but it has a good plot so it was worth it

splinter cell pandora tomorrow for me, 6 hours to beat it.

I beat Prince of Persia - sands of time, in about 13 hours on my first play through.

Luigi's Mansion^^
It took me 5-6 hours, but it was fun. Mostly.

brothers in arms after 2 lvls i was already bored

Gungrave
I finished it in an hour

I think that Katamari Damacy is the shortest game I've had the pleasure of playing.

Devil May Cry 2, I gave it back to the shop on the same day(not because it was terrible, but there was absolutely no replay left for me.) If memory serves me right I clocked in at 2:30.

And a game that isn't really short but I still managed to beat it in 5 hours. Resident Evil 2, I loved that game so much I just locked myself in my room and played it to the end with no breaks. Also, this was before I had a memory card, so no saves for me. RE fans. eat your hearts out, I'm just better. (kidding, don't flame me)

Diablo 1 only 3 hours but it can be replayed a lot becouse it is alweys different Each time game is completely differnt and its cool

Sadly, I'll have to say Ico.
Even when you take your time, you can finish it in four to six hours.
It's a big disappointment for such a great game.

Time Crisis 2 on the PS2.

Barely an hour of gameplay. =.=

Mine is Valkyie Profile.I just use 1 day can finish this game and get ending A ...

devil may cry series on normal

True Crimes: Streets of LA

Full Metal Alchemist: The Broken Angel. To me, compared to the other games I owned, it was the shortest. What else is so weird is that my friend couldn't even beat it, and it was HER game! I told her the only reason why she couldn't win is because I had mad skills like my daddy and she had no good gaming experiences. Of course, after that she beat me with her purse and pouted. '

Zone of the Enders, finished it in 4 hours...

For a single playthrough Megaman Zero 2 and the two GBA metroids are fairly short, but you play them over and over. I've played a few 2 hour games and its kinda dissapointing they're so short, especially if they are good.

Zone of the Enders. Finished it the day after I got it. I was a tad disappointed, thank god for the replay value.

My brother played The Bouncer it took him like an hour and a half and Star Wars Racer Revenge wich took like an hour.

kirby superstar or megamanX1
each i can finish under 5 and a half hours

Not to sure.. coz all my games dun last for 1 mth.. coz starts to get very bored..