rtcvb32: Consider, a lot of NES and SNES games are actually pretty short. Some of my favorite games are Megaman 2, and Megaman X. Both can be beat in about 2 hours.
And then you look at games that are inspired by the retro on work on their own ground asociating themselves with old genres, like Charlie Murder, Rogue Legacy, VVVVVV, Paraunormal Activity, or Duke Nukem Forever take about 6 hours or 8 to be done or a gimmicky one like Asura's Wrath doing the same.
Then again I may be complaining about current games when I played most of the GBA library in which there was Golden Sun, Metroid: Zero Mission or the other series' titles, Wario Land, Medabots Kabuto Ver, Astro Boy Omega Factor, games which all of them took just one day sit in to finish but if you wanted to roam around the game would take you a week to finish.....also having to mention Castlevania Circle of the Moon for a frenzy of rage for me choosing to do the latter.....I was yound and thought I needed the money.
Wait, even Deus Ex can be played in like 8 hours or so, well of course, it's a pain in the ass, considering how difficult it is to beat a damn drone, let alone a upgraded agent, but it's possible, just need to rush down when failing a mission on the places there are the upgrade cannisters but maybe now I am just going off the side of speedruns.