This file talks about how should you make your levels and what to include in them.
- The progression of episode 1 will probably go like: Streets, gradually to an evil corporation's HQ. It happens in New York, in the winter.
- The enemies should start to not be humanoid when you enter the HQ portion of it (Around E1M4).
- Levels start and end with portals if they don't end with a segway into the next level (look at E1M1's end for example).
- Monsters are going to be human around the first few levels of play. For instance, convicts with riflles and shotguns and scientists with volatile concoctions (to replace Serpentipedes).