The Marathon engine is a portal-based, 2.5-D graphics engine that renders environments in two-point perspective. Slanted surfaces and free-floating bridges are impossible, but both can be approximated with creative use of Forge, the level editor. Changes are constantly being made to the engine, because Bungie has released its source code. For information on the ongoing development of the engine, visit the Marathon Open Source site. Engine Limitations: 1024: The maximum number of polygons per level |