Hi there,
Thanks very much for giving my game demo a try and I'm glad you enjoyed it so much. I'm working hard to make it better and finish it.
As for the elevator glitch, it happens when you die after taking the elevator upwards and it doesn't reset when you respawn at a save point. If this happens you should still be able to get the chest that is accessible once the elevator has been raised. Then you'll be able to access the door on the far right of the dungeon and finish the demo. Tbh, you haven't got much left to do in this demo, maybe another couple of minutes.
If this isn't the case and there is another issue besides this one please let me know some more details (maybe some screenshots if you can).