Disclaimer: This article is purely, 100% my own opinion. I don't hate the movie, I just thought it's blah and had a lot of potential. It's a shame that the got a lot of details wrong. If you disagree with any of the points below, please share your thoughts in the comments.
Assassin's Creed the movie, released in 2016, is (supposedly) inspired by a video game by the same name. Starring Michael Fassbender and Marion Cotillard, it got the fans all excited when it was first announced. However, it fell short of expectation. As an avid fan myself, I can't ignore the details that the movie got wrong.
1. The ring finger: The removal
There are many things wrong with this scene in the movie. It is true that the original design of the Hidden Blade initially required the removal of a ring finger, both as a means of more easily extending the blade, and to show the commitment of the one wielding it. However, the movie is set at 1492, during the Spanish Inquisition. During which time, Ezio already found the blueprint of the improved Hidden Blade's design that NO LONGER require the removal of the ring finger (see point 4).
2. The ring finger: Not the 'right' side
Anachronisms aside, the ring finger being removed for the Hidden Blade, is always, always, ALWAYS the left hand one. This is because the original hidden blade is only used on the left hand, and the right hand is used for everything else (sword-fighting, etc).
The removal of the ring finger is also bizarre in the movie, because towards the end, Aguilar use 2 hidden blades (this apparently was his signature move). Shouldn't he remove the ring fingers from both hands then?
3. Master or apprentice?
Aguilar had his initiation some time in the middle of the movie, which was represented with the cutting of his ring finger (yes, I can't let this one go). Which is again, a confusing timeline. This initiation (induction) is originally for a new member, and NOT for a senior member going for a mission (like what Aguilar is going to do in the movie). Does it mean he's a new member? But he's too old to be a new member? Induction of new member is also always accompanied by Leap of Faith, which is not possible in this scene since they're in an underground dungeon.
And as I mentioned, Aguilar also used two Hidden Blades. The right to bear two Hidden Blades was reserved for those who had earned the rank of Master Assassin. So, he's a Master Assassin then? Or the timeline of the movie is just confusing?
4. Apple of misunderstanding: The size
First of all, the size of the Apple of Eden is slightly bigger than the palm, around the size of a grapefruit.
While the movie takes the name "apple" a little too literal and shows that it's only slightly bigger than a lemon.
5. Apple of misunderstanding: The use
Secondly, while the Apple certainly can influence people, it works more like the Jedi mind trick: it only works on the weak minds. And this is not the only thing the Apple can do. It can also gives out energy blasts, communicate with people, and showing them the products necessary to make the technology and transferring wisdom about the manufacturing of devices. This is how Altair able to improve the design of the Hidden Blade, so the Assassins didn't have to cut their ring finger anymore (go back to point 1). The movie gives the impression that the Apple's use is to control humans by stifling their obedience.
6. Missed chance with Ezio Auditore
In 1491, Ezio Auditore, the character from the 2nd Assassin's Creed game, ACTUALLY traveled to Spain. I understand that the movie does not want to be linked with the game stories. But to ignore Ezio, the much-loved character from the series, is a suicide mistake. The movie even mentioned King Muhammad XII of Granada and Queen Isabella, whom both were featured in the game. How could they ignored Ezio entirely?
During the present-time scenes where Callum Lynch was having lunch in Abstergo facility, there were even Assassins from other nationalities, a black guy and a Chinese (descendants of Jean-Baptiste/Adewale and Shao Jun?); I can't believe they wouldn't even feature an Italian Assassin just to pay homage to Ezio. Do they hate Ezio that much?!