Gamasutra posted an article called Making a Case for Short Games, in which the author of Strange Adventures in Infinite Space expounds upon the virtues of short games.
Now, I'm on board with a lot of what he says, but using this game as the example undermines his argument. SAIS is a fun game, to be sure, but I don't think I've ever played a game that drove home the need for longer gameplay than that one. SAIS is basically the moral equivalent of a quick jaunt into a dungeon in a standard RPG; you start out with certain small abilities, you go exploring, you fight some stuff, get better equipment, and then come back out when your resources run low. But unlike most RPG's, the game ends when you get out of the dungeon.
I don't care for that. Most games you play, you visit five to ten stars, where something random happens to you, and you get back home either buff or banked out, and your score gets tallied. Sometimes, you'll get some great item that you never get an opportunity to use. I'd much prefer a longer-form game that allows me to explore more of the so-called "infinite" space, put the buffs you earn to good use, and generally have some more continuity to the game. Just when the game feels like it's getting going, it ends, and you're bumped back to square one for the next game.
There's certainly a middle ground between a 50-hour RPG and the 20-minute game. SAIS's charm is that it's unpredictable and random, so it wouldn't suffer the "story games go on the shelf after you've played them once" fate. But ultimately, SAIS is just too short. They didn't have to make it as long as Escape Velocity Nova to distinguish itself - an option to control the length of the game would have been a simple matter to add, and would allow people to adjust the length of game they wanted to have.