I think that ~10 hrs is also a good number to aim for.
It took me about ~25 hours to finish the Warcraft 3 campaign, and it was great. I also played some adventure games many years ago that I beat in about 2 hours -- that simply isn't enough, especially for a game that has little (immediate) replay value.
Of course those numbers aren't set in stone: For a freeware game, short gameplay isn't nearly as big of an issue as a fullpriced retail game. With freeware you're happy you got to play something good-but-short, with retail you feel cheated out of your money.
I also put up with much shorter gameplay if the game has a good multi-player mode. I played Descent & Descent 3 to death in multiplayer mode, but could never be bothered to finish the campaigns because playing against the computer wasn't nearly as interesting as playing against other humans. As a matter of fact, Warcraft 3 and "X-Wing vs. Tie-fighter" are the only two 'action' games that I can remember ever finishing the entire campaigns for.
Open-ended games are a category all by themselves as well - a game like Tetris that has no real goal other than to stay alive and rackup the points for as long as you can. "Just oooone more game" -- sound familiar? Nothing really changes, it's all just more of the same, but they can entice for literally hours on end. But an important aspect of those games: I still feel cheated when I played Qwirks (some Tetris-style thingey) to an unplayably fast level, ending up with 1.5 billion points. Breaking my all-time high record by a landslide. (Previously 850,000,000). Then I found out that the highscore table couldn't handle numbers bigger than 999,999,999 , and it recognized my 1.5 billion as 500 million instead, and didn't think I qualified for the highscore table. When making an open ended game, one should be able to handle ridiculously high scores, because *someone*, *somewhere* will get one.
It took me about ~25 hours to finish the Warcraft 3 campaign, and it was great. I also played some adventure games many years ago that I beat in about 2 hours -- that simply isn't enough, especially for a game that has little (immediate) replay value.
Of course those numbers aren't set in stone: For a freeware game, short gameplay isn't nearly as big of an issue as a fullpriced retail game. With freeware you're happy you got to play something good-but-short, with retail you feel cheated out of your money.
I also put up with much shorter gameplay if the game has a good multi-player mode. I played Descent & Descent 3 to death in multiplayer mode, but could never be bothered to finish the campaigns because playing against the computer wasn't nearly as interesting as playing against other humans. As a matter of fact, Warcraft 3 and "X-Wing vs. Tie-fighter" are the only two 'action' games that I can remember ever finishing the entire campaigns for.
Open-ended games are a category all by themselves as well - a game like Tetris that has no real goal other than to stay alive and rackup the points for as long as you can. "Just oooone more game" -- sound familiar? Nothing really changes, it's all just more of the same, but they can entice for literally hours on end. But an important aspect of those games: I still feel cheated when I played Qwirks (some Tetris-style thingey) to an unplayably fast level, ending up with 1.5 billion points. Breaking my all-time high record by a landslide. (Previously 850,000,000). Then I found out that the highscore table couldn't handle numbers bigger than 999,999,999 , and it recognized my 1.5 billion as 500 million instead, and didn't think I qualified for the highscore table. When making an open ended game, one should be able to handle ridiculously high scores, because *someone*, *somewhere* will get one.