Why does Halo 2 look worse than Halo 1?

Halo 2 is a video game released in 2004. It is the sequel to Halo 1, a game made by Bungie and released in 2001. Halo follows the story of John Halo (master chief to his friends) as he and his pal arbiter do something, I dont know. There are many shadows such as Stencil shadows and Baked shadows. The Covenant want to steal the...