Well, the concept so far as it's been explained to my understanding is that this isn't the first Destiny game, it is the only Destiny (at least for a decade). Over the course of the next 10 years, through various expansion packs, we will explore, progress the story, and retake the Solar System, aquire new gear, multiplayer will evolve, etc. Basically they want to make sure the Destiny we're still playing in 2020, is the Destiny we're used to from 2014. I have a feeling there are still several planets (and locations on planets) that we've yet to see. Each planet is probably HUGE with tons of stuff to do, and so far we've only witnessed parts of one single mission per planet.

They've definitely concentrated on Earth, the Moon, Mars & Venus, but they've also shown footage of Mercury (via a cutscene), as well as a mysterious region known as the "Reef", whose location is currently unknown. Given that they haven't expanded too much into these areas, yet they obviously factor into the game, I am confident that Bungie is playing things close to the vest (in classic Bungie fashion) & we will be playing in the surface of Europa, as well as within one or more ships in the derelict Cassini fleet orbiting Saturn, during this first game. In fact, I suspect that the first game will take us all throughout our solar system & that the [i]next[/i] game will actually see us moving beyond it and out into galaxy to take the fight to our enemies.

From what I can tell, each area in the game is massive, and there are multiple areas per planet (for instance, Old Russia on Earth probably isn't the only place you can fight Fallen in). So since we have at least four planetary bodies to choose from, I'd say we will have quite enough space to play on for a few years. That said, I imagine future games will spread out a bit, after all it's great marketing to tease an entire new planet. Just think about it: "After nine hundred years, Pluto is a planet again." Cue badass music as Guardians fly to Pluto, which is covered in Vex buildings and stuff. Then there's an awesome battle, and it cuts out to the release date.

Each Game & Comet represent the expansion throughout the universe, so think solar systems. Base game comes with an initial release of planets/moons/stellar objects (Reef, meteor belt). Remaining planets/etc will be released through DLC. Each planet contains a unique set weapons (1000+ in all to collect) ... do make sure you buy every game + comet + DLC to get access to all weapons. You [b]DON'T[/b] want to make the leap from game 1 (with the noob pistol) to game 2 only to find yourself being owned at each turn. What will be interesting though is seeing how bungie manage to sell us Mars (one red dusty battle field) and then get us to buy PlanetX (another red dusty battle field) in the next solar system without it being seen a nothing short of buying weapon upgrades.

We'll I think your on the spot with the latter one. There isn't much more in our sol system. So may by more in the next game.