These are valid points, but playtime doesn't matter to me as long as the quality is there. I actually like shorter games for the most part (minus RPGs....I like those long).Other games have very high production values and a bit more length and replay ability.
Not saying the game should be RPG level 40 hours long, but it should at least be closer to the 10 hour mark OR have some type of new game+, unlockables, co-op, side missions, or something to add to the value. MGS ground zeroes was similarly short but it had a hell of a lot more replay value and it only cost $20 and people still complained about that one.
I may be in the minority here though
