It's normal. It's kinda like you're opening the rom in a hex editor, but instead of seeing hex values, you see 8x8 tiles. That's the way the graphics are stored.
Sometimes, there exists a game specific editor, which is way easier to use, but I couldn't find one for this game.
Metroid: Other M. June 27th, 2010.
Delayed - August 31st, 2010.