Depends. You're justified to quit after five minutes, if you feel the mechanics don't work for you. Overall, 2 hours is more than plenty to get a handle on a game. If a developer hasn't managed to grab your attention by then, it's not your fault.
Which is interesting, because there are exceptions; Final Fantasy XIII being a very good one, which doesn't even get to the meat of the gameplay and has half the mechanics locked away for the first couple of hours of gameplay. But that's still their fault.
Which is interesting, because there are exceptions; Final Fantasy XIII being a very good one, which doesn't even get to the meat of the gameplay and has half the mechanics locked away for the first couple of hours of gameplay. But that's still their fault.