I felt that, like the first one, the whole idea of the film was good, but just lacked in execution.
The problem here, again, is that you're in one remote setting, and the dialogue being used is just not all that interesting. The Joker's development from the first film to this one has been dismal at best. There has been nothing new added to the character. The whole manipulation bit is old. It was done to Harvey Dent in TDK, and it's been recycled twice now in both of your efforts.
I've said this before, but if you're going to use a Heath-inspired Joker, there has to be some sort of new dimension added to him, otherwise it is just boring and stale to watch.
Staying with character development…Harleyâ€⠄¢s seems to follow the exact arc from the first film. To start, she’s hesitant, confused, and unsure of which path to choose. By the middle of the film, she’s still hesitant, but leaning towards the Joker. By the film’s end, she has completely jumped to Joker’s ship. This was the biggest flaw in your film. It’s rehashing the same ideas with a different setting. Not to mention, she develops too fast. The lack of build up ends with a flat pay off. One minute, she’s refusing to kill the guy, the guy asks for help, she (seemingly for no reason) snaps, and all of a sudden is on Joker’s side again. It’s almost out of nowhere that this happens.
I see the effort, but I think it’s time for the director to move on and leave this incarnation of the Joker alone. It would be different if they director/writer was trying to take the Joker character somewhere new, but these films haven’t done that. With Harley added, a different dimension to Joker should’ve been expanded on, but it wasn’t. And it seems that the writer director/writer just don’t know what to do with the Joker persona outside of reviving what has already been done in TDK.
Overall, the film is mediocre at best. There is nothing in this film that adds new life or takes a different turn on either of the featured characters, and the creativity seems lacking as the premise for this film and its predecessor are seemingly the same, minus the “kill the doctor to prove you love me” plot tool. I think it’s time to move on…