Wait, there's more than one alternate world?!? I just jumped to one world and then back. I need to explore more!
Yes, there are more than one... It's kind of tricky but you can activate the device and make the right settings to portal off again. Once you've done it and got the settings in the notebook (small paper bits are moveable - hint), it's easy to do again. If you try and get stuck I'll help you out ;)
Thats how you could got back to the world and pyramid again. If you do the whole game the device can not be activated after returning home. I have not been able to understand the bug that makes it possible to pre finish the game. Many players who get the short ending seems to have a decent experience anyway so I've left it at that and hasn't lifted the game out of Beta status. It's been a while since last tampering with it, maybe I'll see something new looking at the other bugs. Maybe, maybe a string value connected to the device, as you saw something there, it's a trail I haven't analyzed so far...