I saw the movie earlier and I found it overall decent. Not bad, but not great either. I'm far from a critic and I'm not too picky about movies, but this post popped up in my feed, so this is just my two cents as someone who generally enjoys Markipliers content and his previous larger productions.
I personally found the visuals and especially the camera work quite good, I didn't actually mind the fact that the camera never left the submarine (although maybe it would have made for some more exciting shots). I thought the sound design was pretty good as well.
The story (or lack thereof) was the weakest part in my opinion. The first half was pretty uneventful and the second half was too random and disconnected for my taste. It left me feeling like I didn't really get what went on in the end.
In the end, I'm happy that I saw the movie and I think it definitely showcases some good skills, but with a lot left to improve :)

In case someone tells you to eat a bag of dicks