Its up to you, not everybody will like a game, although as I love the Civ series I find your problem a bit hard to understand. The thing to remember is a civ game is a bit of a slow boiler, when an individual game can take many hours (and I have seen games that have taken over 300 hours) playing for only 10 minutes isn't really giving it a full shot.
I think you have to examine your reasons why you downloaded the demo in the first place, if it was just curiosity then it could be the game is not for you. On the other hand if you are looking for a game to play as you don't have anything else to play then you should probably give it a couple of hours.
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