This might easily be one of the most nihilistic flicks i've ever seen. Despite IMDb currently labelling it as 'horror thriller', it seems it was supposed to be more like a mixture of slasher/thriller, drama/romance and a bit of comedy. However, it fails at each: It's thriller without suspense, a slasher without on-screen killings, a drama/romance without any tangible emotions, a comedy without one laugh.
Bland story made of generic thriller tropes, while the writers constantly deny the number one rule in screen writing - "SHOW, DON'T TELL!" - in a way that basically all information (characterizations, their relationships, motivations, background story) are merely given in form of dialogue. If you can't SHOW a story, but only TELL it via dialogue, you should rather release it as a book or radio play, instead of shooting an audio-visually dull movie like that.
Oh yes, since the movie takes place on a luxury liner, i was at least expecting a rather fancy set - but no, most of it are just boring medium shots of talking characters...
Bottom line: The only positive things about this movie are its shorter-than-usual runtime and the actors still trying to make a professional job, while anything else appears to be carried out on amateur level.
By the way, note the "mirror scare"! You will probably not get a more nihilistic variation of this horror trope anywhere - which is very exemplary for the entire movie.