Saturn - What if there were a social space of nothing but Xurs? Better yet, what if in that expansion/sequel upon going there, we learn more about the Nine and how they operate, and then we learn more about Skolas and his escape from them? As far as gameplay goes, I would have trouble imagining Saturn. We know there is the dead ship in its rings from Concept Art? Maybe we'd explore that. From there I could imagine it sort of being like Dead Space where it's a pitch black ship/station and the Hive are everywhere around us. Then we can go down to the surface of the planet and meet the Jovians in a world that is unlike any other from their technological advances. Jupiter - Based on Concept Art, we've seen its moon, Europa. It looks like an "ice world" almost. I'd imagine seeing some snowy disasters, such as Avalanches. Personally, I'd love to see some Vex there. As far as story goes, maybe upon arrival we could see some frozen Vex around us, and then the Vex come alive again later on. Then we explore and find more about what the Vex have done with Jupiter's moon, and find whatever we can about the Golden Age. Maybe we could also smash the Vex while they're frozen? I think that would be interesting. Neptune - This is one we've seen no concept art of, but nonetheless I have some ideas for it. Being a gas giant with no solid land, what if it were a space battle? Imagine this: There is an enemy outpost inside of Neptune. We then go there in our ships, and upon entering the gas giant, it instantly blocks our COMs. We are in our ships, and then we actually get to fly our ships around a "foggy" area inside the Gas Giant. We get to blow up Skiffs and such, and then we finally board the enemy outpost. Essentially I would see Neptune as a twist of the one mission in Halo: Reach. I know these are very vague ideas, but I'd still love to see what others have thought of for these planets in our game.