Here's another guide, this one gives you the location of all the Dark Matter chests and a guide on all the new heartless

 

http://www.youtube.com/watch?v=GbzrH0BufnI

Note: Unmentioned strategy for Gigas Shadows, good method is using Dumbo. Regardless of your level long as your gauge is long enough (I have 2 cheers and it's suffice), they can't hit you while you're on him and you just do 360s hitting splash.  I haven't lost to them at all since I started using that method and get 2 fury stones all the time (:

Note: Unmentioned strategy for Gigas Shadows, good method is using Dumbo. Regardless of your level long as your gauge is long enough (I have 2 cheers and it's suffice), they can't hit you while you're on him and you just do 360s hitting splash.  I haven't lost to them at all since I started using that method and get 2 fury stones all the time (:

 

Noted