Over the Net

Yes. Over the Net is free to play on Steam, so there is nothing to buy to start playing.

The minimum requirements for Over the Net are: Windows 7, Intel Core Duo, 2 GB RAM, 410 MB storage. It runs on Windows only. The recommended specs are in the System requirements section.

No. Over the Net is a single-player game.

Mostly, yes. Valve rates Over the Net as Playable on the Steam Deck: it runs, but may need some manual setup.

Yes. Over the Net is the full base game. You need nothing else to play it.