Roofed

This story is quite short, and the locations are clearly limited.
The special thing about it are the responses and actions of the central NPC, your sidekick who shares the fate of the story with you. They appear funny and brighten up the gameplay without ever becoming annoying. The NPC is well intergrated into other aspects like the hint system and the puzzles which cannot be solved without interaction with the NPC.
This is an excellent example of NPC integration.