As a long time FNAF fan and theorist, I personally think that the movie was a fun and exciting watch, 10/10, I got so excited I actually started shaking in the theater. I watched it a couple of days ago and since then I’ve rewatched it about 2 more times, which has given me the opportunity to fully take in the movie, and I’d give it about a 7.5/10 (the 0.5 is just me being generous). Don’t get me wrong, a copious amount of love was put into the production of the film. The sets and the animatronics themselves were all done practically in order to keep CGI and computer based effects to a minimum, and it really paid off in the final product as the visuals are nothing short of incredible. Especially considering it was accompanied by such a talented cast, but it's the story/writing and pacing that let the whole thing down.
It felt like 90% of the film was just fan service (As producer Jason Blum said himself, the movie was made just for the fans) but even then I feel like it did it a detriment in the end. Sure, there were a-lot of cool easter eggs from across the FNAF franchise that made appearances, however in turn it took screen time away from the aspects of the original story that mattered more. In addition, the overall story of the movie felt kind of broken. Parts of it were missing important context and it didn’t help that there were a large number of characters that were written into the screenplay that were never in the original or originally had a completely different role/were in a completely different part of the timeline (which sounds fine on its own, but was executed poorly). I just feel that some aspects of the film didn’t mix well and it made it feel shallow at times.
I’ve also taken the time to do some research about the movie after I saw it and apparently there were a-lot of scenes that were cut from the final version to prevent the film from dragging on, since it was originally slated to have a 3 hour run time. Still, the film definitely had the time to be so much more given their resources. The thing that confuses me the most is that Scott himself had to specifically approve each and every little aspect of the film before they went ahead with it, so I’m not sure why he chose to go with that route. But I’m just hoping his plan pays off in the long term I guess. Again though, as a FNAF fan I liked it overall, and I was a REALLY big fan of the ending sequence.