Don't worry, Sand Land is much better than its dreadful demo, but maybe read the Akira Toriyama manga first

You can play a demo of Sand Land on Steam right now, but I wouldn't recommend it.

The three hours I recently spent with a preview build of Sand Land were a lot more promising than what's publicly available right now: I agree with most users on Steam that it's a bafflingly bad demo, dropping the player into a drab world with three spawnable vehicles and a bunch of giant enemy crabs and dinos to shoot at. It soured me on the prospect of this adaptation, but thankfully my hands-on with the full game piqued my interest again...