Guerrilla War for NES.

house of the dead on pc. finished it in 30 minutes, on the first playthrough.

Medal of Honor: Rising Sun was like that too, it was back at the store by midday the same day i wasn't getting stiffed out of $90 for something so short and it wasn't even that good

Resident Evil 5 and Quantum of Solace.

Medal of honor: hero's 2 is easy even on hard. Pistol/shotgun/ grenades only run makes it slightly more difficult but You could breeze through it playing normally. I occasionally used shotgun when I ether ran out of ammo for the pistol or because I was sick of it. Like wise with grenades though rarely. Most of the levels I have beaten with just a pistol. It does make the Nazi's look pathetic when a guy with a pistol takes them all out.
Condemed:criminal origins took me about 14 hours to beat though not at 100%. I believe one could do better than that and that was on hard.
Dreamfall: The longest journey might be one of them as I hear it is short and takes around 20 hours or less.

It is a game. It's just on the blurred lien between "game" game and "art" game

Oh I forgot Clock Tower 3.
Relatively easy survival horror game with the final boss from hell. Honestly, just a broken-hard boss - IMO one of the worst. You have to save all your items throughout the game to have a prayer of beating him.
The other is Haunted Castle. I love Castlevania. I can obliterate all the CV games. I can't beat the first level of that one.

Resident Evil 2 - Beat in 2 days when it first came out
Modern Warfare 2 - Beat in 6 hours. Thats with replaying the No Russian mission to show my wife, and the starting Brazil mission again.
Halo - Save for the flood, very very easy game, with repeating enemies.
Uncharted: Drake's Fortune - Great game, but also very short and easy if you're good with 3rd person shooters.
As for difficult.....
I wanna be the guy - Nuff said
Fatal Frame - Not hard, it just scares the shit out of me enough times I have to put it down and stop playing for awhile.
X-Com UFO Defense - I love the game, but it's insanely difficult for me. The night missions are horrible, since the enemies always see you move and shoot you, despite the fact that you can't see them.

New Prince of Persia. Easy to play in a therapeutic way.

torchlight, same reason