I have updated the demo again.  It now contains a bit more explanation of what makes it a demo, and how it differs from the actual game. 

Basically, the demo generates a galaxy, just like the full version of Star Explorers.  However, it limits the amount of warp fuel in the player's ship, allowing it to visit only one star system before running out.  While near a star, the ship can use "solar engines" to travel from one planet to another, but it will not be able to return to the mothership, or visit other star systems.  

This way, you can see how the game works, and even do a bit of exploration to see how things get generated procedurally.