In case you missed the Kickstarter for the eerily beautiful post-apocalyptic industrial Rain World, below is a short Alpha trailer to get you acquainted.
Rain World collected $63,255 through Kickstarter, shattering their goal of $25,000. Because they raised so much, the Project Rain World team can afford to translate Rain World to C#/ Unity, meaning that they can do a lot more fancy stuff with their game, and make it available for more platforms (See: Linux). In the process of translating Rain World, the lead programmer decided to dip his toes into C#/ Unity by taking assets from Rain World code and making a small test game called Space Worms that you can download for free. It's not a demo of Rain World per se, but it's really cool of the development team to give fans access to the milestones of their project and to be so transparent with their process. The team says it a lot better than I can in their Kickstarter update:
"the art, sound, AI and menu assets are all handled using what is basically Rain World code, so Space Worms has been a fantastic proof of concept and teacher for us, allowing Joar to test how Rain World code will function in C#/Unity without having to tear apart the original or littering the new Rain World build with the learning process."
You can download Space Worms through their Kickstarter Update here.
If you're into following devlogs, you can keep tabs on Joar on the TIGsource forums.