Kudamono Party

Yes. Kudamono Party is free to play on Steam, so there is nothing to buy to start playing.

The minimum requirements for Kudamono Party are: Windows 10, Intel Core i3, 2 GB RAM, 200 MB storage. It runs on Windows only. The recommended specs are in the System requirements section.

No. Kudamono Party is a single-player game.

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

Yes. Kudamono Party is the full base game. You need nothing else to play it.