Hi there! What you consider adding a FPS game to make it more realistic? E.g.: background sounds, player get tired if running after a while, lights, player can not jump repeatedly, etc.
I think with Superku's hitzone, some great modeling and animation and some top notch fxs. You could create a close quarters fps that is extremely violent and realistic. With 3dgs using a lowered poly set could allow a mix of cartoon like and super real fps action. You'r other suggests are also great for this.