I thought most games took 8 hours to beat or less? Not sure what the point of this is unless you want to get *really* short, like 20 minutes or less for your average player.
I'm actually thinking more along the four hours or less variety, but I didn't know how many games actually fell into that category. Twenty minutes sounds like a good per session time though. But that's just adding way to many parameters to the mix.
Really how many games out there can give you satisfying play in a <= 20 minutes session and take less than 4 hours to complete?