Play AC1 1/3rd of the way through, then drop it and go to AC2. AC1 does a great job of establishing the core idea of the series, the story, and the gameplay. But execution-wise it is VERY weak. But I think it's important to play the game to see how the series started, and to have something to compare AC2 to. 50% of my enjoyment of AC2 was being floored at how much better it was than AC1. You can't get that without playing AC1.
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_foolmo_
'I love you so much' - SineNomine