The Last Promise

Yes. The Last Promise is free to play on Steam, so there is nothing to buy to start playing.

The minimum requirements for The Last Promise are: Windows 7, Intel Core 2 Duo, 2 GB RAM, 2 GB storage. It runs on Windows only. The recommended specs are in the System requirements section.

No. The Last Promise is a single-player game.

No. Valve rates The Last Promise as Unsupported on the Steam Deck.

Yes. The Last Promise is the full base game. You need nothing else to play it.