A game with the art style of those Harry Potter LEGO game cutscenes. (Cardboard cut-out characters bopping up and down on a multi-layered background. Like it was made from cardboard/paper and placed behind each other.)
It’s probably about fighting, or stealing, or something.
Idea 1: You can “go down under”. Your character disappears under the playing field, and you can move unseen. (By others … but also by you.) When you press the button again, you come up wherever you are now.
Idea 2: When someone is knocked down, their cutout-character folds in half (along the waistline).