The screen splitting is extremely fluent and seamless too! I would like to dig into the source code and find out how you achieve this. What tools did you use to build this game?
I made the game with Godot Engine, you can get the code from github and explore it a bit.
The camera split is a trick, it works rendering two viewports one in front of the other, then the front one has a shader which renders or not depending on distance and angle between the protagonists.
I hope you liked the solution and the code, leave more comments if you like.