It depends on what you mean. You can't unlock areas through game progress. The game doesn't work like that. If you have it on xbox 360, and you have xbox live, you can go to the marketplace and buy expansions such as knights of the nine, shivering isles, and the Orrery or the Wizards tower. You can download them online if it is on a pc, but I do not know the website.
Buy or find them.
you can't Oblivion's shop is not completed as of this date. Terces is a working project and will be finished eventually.
Codes can only be used once and then they burn them into oblivion.
you got to discover them by walking to them, a very tedious task.
In "The Elder Scrolls IV: Oblivion," you can unlock all doors and containers by using the console command. To do this, press the tilde key (~) to open the console, then type tcl to toggle collision off, allowing you to walk through walls and access locked areas. If you want to unlock all keys specifically, you can use the command player.additem 000A8C4C 1 for the Skeleton Key, which unlocks all locks. Remember to save your game before using console commands, as they can sometimes cause glitches.
Yes, You unlock them by advancing in the Story.
it doesn't matter what level your player is but it does depend on what areas you go to, but in oblivion your level of difficulty depends on how strong the daedra are.this is from experience. im a level 40 sumthin nord.
there are alot of other gates you have to look for them
I blew them to oblivion with an atomic bomb; they were blown to oblivion; the Universe was sucked to oblivion; its like they appeared out of oblivion
As you progress through the game you will unlock more areas.
open console (~ key) then type this in quotes "togglemapmarkers 1" then that unlocks all the places on your map :D have fun
You can play it while signed into xbox live, but you cant play with other people through xbox live on oblivion.