Lighting and shadow is looking like it's from the old Minecraft.

I decided to go to Minecraft version 1.0 to check it out. It looked cool. I close the old Minecraft and change my snapshot back to the current snapshot. When I entered the world, it was bright and the shadows became chunky. Like the old Minecraft, I was in. Everything looks fine but the lighting did not. How do I fix this? I do not want to be in the old Minecraft lighting all the time. I tried to do the "Erase cached data" and it did not work. Please help!