The UI thing you mentioned is because I was lazy.
I already made all the items and only after decided they were too small, so not wanting to change the size of every single item, I just scaled and positioned the VBoxContainer node that holds all of the scenes. That doesn't work very well if you play a different resolution.
To make it even worse, I used an AnimationPlayer to smoothly interpolate between a negative and positive x axis scale, so I would have to change every keyframe. I designed the game around 1152x648 and did not have time to refactor that entire system.
Thanks for the feedback!