Spoiler warning/tangent:
I had zero interest in seeing this film when the trailers dropped. Over time it grew on me and thought "hey this has exploitation written all over it. I'll go see it."
So I'll get into the good first.I thought the set designs were well done. Very minimalist to keep your attention on the characters. The pacing is great (except for the ending, I'll get into that). I really enjoyed the idea of a drug that can split you in two, a very well done "science gone wrong" theme. I was really hoping there would be more gore effects, the film really leans into T&A but it's tastefully done. Side note, I think Demi Moore looks great. I prefer her over Margaret Qualley (that's just my personal opinion, just like how I feel about the ending...). Dennis Quad I would say gives the best performance as a slime ball producer.
Okay the negatives/tangent/spoilers: I really hated the ending. I personally believe the movie should have ended when Sue injects herself with the activator and turns into a Cronenberg monster. The last 20-30 minutes of that film (good grief that felt like an eternity) really hurt the pacing of the film. It takes a complete nose dive. I know the film is an allegory for beauty standards on women but the film should have been more subtle like the movie 'Brain Damage' (an allegory film on drug abuse). It becomes way to on the nose and turns into a fucking Kent Russel wannabe film. I kid you not, I almost started yelling in the theatre "HOW THE FUCK DID THIS FILM WIN BEST SCRIPT?!?!".
All in all, I enjoyed 'The Substance' up until the end. I highly recommend you get up and leave the theatre in the last 20-30 minutes.