kusumahendra: If I have to spend 5 hours in one mission I probably will drop the game :)
Fortunately it's Dishonored you're talking about so it's kinda understandable that you stick with it
Well, you may know that each mission can be completed very quickly, but the great gameplay and the approach freedom the game gives you, all lead to prolonged gameplay sessions with multiple quick-loads.
("hmmm, let's try this -- F9 -- hmmmm, let's try that -- F9 -- maybe if.... -- F9").
As for whether or not you'd probably drop a game, have you played Supreme Commander? The campaign starts easy with a small map, and when you think you'll get a "Mission Successful" and go to the second map & mission, it just opens a bigger portion of the map with updated Objectives, only to have you believe you'll finish it this time which is not true because it'll open a much bigger portion of the map and so on.. I got tired of it quickly (maybe i messed up a mission and didn't want to start it again? can't remember) and just played Skirmish mode.