I own Assassin's Creed II, III, Brotherhood, and IV. I don't think I'll have time to play them all. If I were to just play one, which would you recommend? 

Either the second one or the fourth one. I haven't played Rogue, so I don't know about that one.

The ezio trilogy is the peak if tge series after that it went downhill

Brotherhood was my favorite. It was everything that made II great (except maybe not as good of a story) plus so much more.

Play 2 and Black Flag

2 is the best true AC game, and Black Flag is just a great fun pirate game

I haven't played III or newer yet, but I've played all the previous (main) games. The first one has the best atmosphere by far, while the second one is the most balanced as a whole. When in doubt, pick II. Brotherhood has better gameplay but it's shorter and not quite as balanced as a whole.

III is generally not liked very much, while IV is considered one of the best games in the series, I think. But like I said, I can't speak from experience in regard to them.

Assassins Creed 2 was the best,ending especially for me it was one of the coolest endings imo.

2 is the best in the series for me. Also Brotherhood is a direct sequel to 2, so don't think about playing brotherhood without finishing 2. If you end up playing a second, I believe the Brotherhood is the second best, so that would be a nice follow up to 2 if you play it.

I enjoyed Black Flag the most, ironically it's the one that's least an Assassin game.

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