I'm not really planning on making any boss levels, but I had this idea and I just tested it out and it works great. I've already seen maps that place two boss actors in the same room, but the limitation on that is that you only need to kill one of them to end the level. One boss though is an excellent workaround for that limitation: El Oscuro! He cannot be damaged in human form (for the most part) and can only be killed if there's lava pits in the room in snake form, so he's actually perfect for adding as boss support if you wanted to up the challenge! Just whatever you do, do not put human form in a room with Sebastian Krist, unless you want to witness El Oscuro get gibbed by a lay-z-boy