The defining quality of enemies is that they can be attacked and taken out. By contrast, the defining quality of obstacles is that they can’t. Obstacles make scenes demonstrably more difficult on the PCs, but the PCs cannot simply fight them. Obstacles must be circumvented, endured, or rendered irrelevant.

While most obstacles are features of the environment, some might be characters that can’t be taken out using conventional methods. The dragon might be a boss, but it might just as easily be a hazard obstacle. The animate statue keeping you from getting to the evil wizard might be a threat, but it could also be a block or a distraction. It all depends on the adversary’s function in the scene, and how PCs must deal with it.

Obstacles don’t appear in every scene. They serve to accent enemies in the scene, to make them more threatening or memorable, but overuse of obstacles can be frustrating to the PCs, particularly those focused on combat. You can use them to give less combative PCs something to do during a fight, though.

There are three kinds of obstacles: hazards, blocks, and distractions.