The Artwork.zip folder is various artworks made for the game (which make for some great wallpapers!) but is just a bonus you get access to once you complete the game. But it's not in the game per se, you just get a code to dezip the archive file, so it won't break the game to remove it.
The World1.wmp file is 3 ko so I guess it's not the heaviest thing :D It is not mandatory for the main game, but it is mandatory for the bonus 2016 prototype you unlock by completing the game as well. So removing it would break a bonus part of the game, but I gotta say it's not the most interesting part of it and is just a incomplete messy prototype with probably some game breaking glitches left in i!