Christopher Bird’s review published on Letterboxd :
For the first half hour or so, I watched this and thought "well, it's obviously not anywhere near perfect, but maybe it can be a solid B-movie, a decent bit of disposable entertainment." But then the movie takes a hard right turn into shittiness and just floors the goddamn pedal to drive into turd-town (this metaphor is increasingly unpleasant, but so is the movie, so there you go).
So much about this movie is just fucking embarrassing. Dull, lifeless Michael Bay-lite teal/orange postproduction color scheme? Yep, it's got one, of course it does (all the more shameful when you consider how vibrant most of the games are in comparison). A script that doesn't understand, not even a little, that you need moments of levity to release tension and engage the audience in your frankly silly narrative? Big ol' check there, with a side order of false profundity to boot. Lots and lots of quick cuts to disguise the fact that Michael Fassbender and Michael K. Williams and the others simply aren't martial artists? Of course (and this is the sort of thing that makes you appreciate so much more a Keanu Reeves putting in months of work to be able to do what he does in the JOHN WICK films so convincingly). Plot barely there? Of course there's no plot worth mentioning. Paycheque Jeremy Irons, the worst version of Jeremy Irons? Oh yes.
And let's not forget the central bit of stupidity here, which is that the videogame concept of the Animus - basically, The Matrix except you plug into a computer and relive a past life - wasn't *good enough for the filmmakers*, so instead they made a giant fucking metal arm to give the Animus more of a visual hook. Except, and this is important, it's obviously fucking stupid.
Cheap and cynical and such a disappointment. ASSASSIN'S CREED - the franchise - deserved so much better than this (given that it is basically a vehicle for "do parkour and have cool fights in olden times"), and could have gotten it for less money. In fact, they did - the direct-to-disc movie they made incorporating the three Youtube shorts they made is vastly better than this garbage.