I also added in the player sprites. Before the player "things" were added into the level, but not rendered. After adding support for palette shifting I was able to set player colors and render them. I also added some code to be able to switch camera and keyboard control between players. In the real game in co-op mode you can switch the camera(but not the controls) between team members, so that it's easier to tell where they are.
Here I've moved the green player off to the side and then switched to the brown one and backed up a little to take the screenshot.