This free demo lets you play completely randomized battles. It doesn't include ship design, challenge levels or custom battles.
Extract to a folder that doesn't require admin rights to write files under.
You may need to install Microsoft XNA Framework 4.0 Refresh redistributable from under the "Redistibutable" folder in the zip file.
Microsoft .NET Framework 4.5.2 or newer is also needed to run the game, but that is more commonly already installed. You can get that from here.
Updated versions of the demo will be available from itch.io: