Just take the images from the Colors! directory instead of exporting. It's at the exact resolution of the DS, which is probably why the smallest option in the Colors! DS export menu is 2x the DS's resolution
Only thing drive me crazy is all these new horror games nowadays is its so dark, all time. I can't even play them. I understand they trying to create spooky but be creative a little, not just darkness with pop out scare scenes.