Mapping Quake

The 1st level of Quake starts with a slipgate that transports you to a room where you can pick up ammo and armor, but there is nowhere to go but to a lift that takes you to down and lets you off outdoors. There is a building ahead across a stream. There is a marine and a dog on the other side of the screen. They both will try and attack you without explanation, and you most likely have to shoot one or both of them to get by. There are secrets to find outdoors, like the underwater tunnel, but that ultimately leads you back to where you started. Inside the building, the movement is linear but the path doubles back on itself to utilize the environment. More marines are inside and will shoot you if you don't shoot them down first. The pathway spirals down and back around, ultimately forming a giant loop, which seems to be a good way of using the space of the level efficiently.