If you are big in physics sandbox games, you might want to check out the free demo for Liquid crystal, which was recently announced by Kotsoft. However, the particle physics simulator is alpha, so changes will probably be made before it is formally published, but you can still download it and have fun.
In the world of Liquid crystal, you can run (or fly) around and explore a world made of particles. You can also shoot particles or apply an attraction to other particles, such as spraying water, to see what happens. Each block is physically simulated and interactable with, and it has fairly fast and responsive movements, although it is not a perfect physics simulator (yet).
You can download Liquid crystal demo here on itch.io. Minimum system requirements include Windows 10 64-bit, SSE2 CPU support, a DirectX 11.1 support, 2 GB GPU and 4 GB RAM, although the author recommends Windows 10 64-bit, an Intel Core i7-8700K CPU, an RTX 2080 GPU and 16 GB RAM.
Since it’s a fairly new upload to itch.io, Windows will probably fire the SmartScreen Filter warning when you first try to run it. Don’t worry, though – it’s easy to get around. When the warning appears, click on “More info” and then “Drive anyway”, and you should be good to go.
Source: Grant Kot