The Short Answer
The core game is a local, story driven experience: scenes, dialogue, items, and progression live on your device once the game is installed. That means the heart of the game can be enjoyed without a connection in most situations, while anything that talks to a server, such as downloads, updates, or account related features, still needs data.
The Devastate app homepage guide notes the same distinction in its compatibility section. Treat offline as story mode freedom with a few connected edges, and you will rarely be surprised. The sections below separate what works from what waits for a signal.
