User blog comment:Master Sima Yi/Assassinews 02-03-'12 — Leaked AC3 info!/@comment-4374396-20120305204625/@comment-3979092-20120305225632

If that trailer is just an in game that is awesome. besides after reading the article it states like this: The Anvil game engine has been reworked for Assassin’s Creed 3 to allow thousands of AI characters on-screen to engage in bloody battle. Ubisoft have said that, if they were using numbered versions of the engine, they’ve basically gone from Anvil 1.0 to Anvil 2.0. Animations have received a major overhaul too with Connor having over 1,000 new and unique animations to compliment the new combat system, with none being brought over from previous games.

And they called it AC3.5 because they will refine this after finishing the whole game before they release it in October.