No, it's not a rip-off because it's open world. Games being in the same category aren't "ripping" each other off. But when I'm 30 mins into botw, and I'm like "this is assassin's creed.." somethings up. It's alot more than the fact of being open world that I felt this. Mechanics are the same, gameplay is the same, hell some of AC's most notable features are there.