So i have been thinking of a gamemode so the main idea of it is mostly the same idea as rebound but instead of rebounds it would be portals like A portal goes to A just like the normal portals but maybe a way to differentiate which portal goes where would be to use multiple color portals. So the only way to do damage would have to be with shooting it through a portal but actually now that i think about it there could also be rebounds in it to make it more interesting but you still need it to go through a portal. So that is my idea i think it is pretty simple but also could be as difficult as rebound.