Okay, Let's Put it this way...
Our world is normal. Arceus created the world, right??? Which he created Time/Space, right??
What fits in with Space and Time??
Dimensions.
Giratina Represents Death, Chaos and as well as Dimensions.
Well Giratina is rthe mascot of platinum and as it says in the pokedex:
A pokemon that is said to live in a world on the reversed side of ours. It appears in ancient cemetaries. Well, the Pokemon's home is the distortion world, where Time and Space do not play a roll.
As Space doesn't play a roll, you are able to run on walls, walk through walls, trees and rocks, surf on waterfalls,Jump through to different parts of the world, and you don't find any Pokemon what so ever, and black patches on thew ground will appear with glowing red eyes.And since time doesn't apply,Day,Night or evening does not show.
The Distortion World is A Large Puzzle, and it's quite easy to fustrate yourself.
The Puzzle is to use Strenght on all the rocks. While moving around you may see Uxie,Azelf or Mesprit.Use Strength on the boulders untill the fall into a small hole and freeze, and the pixy closest to you will run.Do this to all 3 Pixies, and fight Cyrus.
After Cyrus will lose, he will step aside. you will hear Giratina's Battle cry. and Three small spots of land will appear. jumping onto the first2, before you move to the third, a basilisk lik figure will fling to the top of the screen.
while on the third spot, Giratina will move up to you, you can save and do what so ever, but you cannot leave Giratina's presence. When you Giratina, it is the battle to save the real world.
Now you'll have to battle it yourself.