SYNTHETIK: Arena is a fully free-to-play, standalone expansion pack for the original SYNTHETIK. Released just yesterday as a sort of a taste of what SYNTHETIK really is, it's perfect for those who've been on the fence about buying it.
SYNTHETIK demo isn't exactly a thing, but Arena is even better than that. It allows for thorough testing of the game's core gameplay features in a separate, dedicated arena mode which players can enjoy for as long as they like without spending a dime.
According to the game's Steam page, SYNTHETIK: Arena has players face off against five unforgiving challenges deployed by the Machine God Zur in an effort to stifle the protagonists' progress in the original SYNTHETIK storyline. Of course, all of Arena is available in 2-player COOP as well, which makes this an even better deal.
All of the progress that players make in Arena ties into the core SYNTHETIK experience, should you choose to buy it further down the line, and for those who are already big fans of the game, there's the Arena Premium Upgrade DLC which opens up Arena in the base game, as well as adding more items and weapons to the mix.
Since there's no reason for you not to give SYNTHETIK a whirl now that Arena is available in-full for absolutely free, be sure to check the game out on Steam. It's a rather niche title with unique aesthetics and gameplay, but you may very well like it.