Are you sure? Because it ends right after I beat Nerov in the parking and he sends Abell and Ceres away with portals and the game says "Thank you for playing the demo." and goes back to title screen...
I checked in case I downloaded the wrong file by error and no, I indeed downloaded the file which doesn't contain "demo" in its name and is twice the size of the demo file but still, the game ends after the first encounter and battle against Nerov and it says "Thank you for playing the demo" then goes back to title screen...
Maybe you scripted an event for the demo to go back to title screen and you didn't remove it in the full game so it stops the game even if there is more?