Marathon Infinity

Marathon Infinity was Bungie's final game in the infamous Marathon series. Its levels were bigger and much harder than in the previous two games, and there were new environmental effects such as zero gravity, vacuum spaces where you had to wear a mask, and so on.

The most dramatic improvement in the game was the inclusion of Bungie's own level-creating software, Forge, and their physics editor, Anvil. Forge and Anvil allowed a new generation of players to create their own levels using the same tools as the Bungie developers themselves.