Exploration-only games and the five-ingredient principle

Removing combat from a game works like removing ingredients from a recipe. When you strip the tension mechanic, the world has to carry the whole load. Layout, atmosphere, discovery logic, all of it becomes structural rather than decorative. That's a stricter design constraint than it sounds. The games that survive it tend to be ones where someone understood the space well enough that curiosity does the work enemies usually handle.
Source: 29 Essential, Must-Play Adventure Games - IGN ↗