Really cool visual style, agreed that it gave me Portal vibes. I think having an option for no residual loss may be a good idea in case someone just wants to see the story and/or to learn the mechanics.
I never quite understood why my reflection was backwards or if it was a ghost or something, a lot of text read as AI speak with lots of repetitiveness and added fluff.
You may also consider adding the option to withdraw power from the powered up object itself instead of having to go back to the main area. Great work!