Nice puzzler, I like the gravity switch mechanic! It’s easy to understand but I can see how you could build some really tricky puzzles with it. I had fun solving the level.
But while the mechanic worked really well gameplay wise, I didn’t really get how it fits with the game’s theme. Why does being your younger self reverse gravity? Does a child see the world upside-down or how is it meant? As of now maybe you can find a way to contextualize the power better.
About the power-meter: are you supposed to lose when it runs out? In the demo it seemed kinda pointless as it would just slow you down a bit but still make the level solvable once empty. If you want to include it, I would tie it to a loss condition - but my feeling is that the game might be better off without it. Maybe you can use it for a new game+ challenge mode instead.
The art style looks pretty good already for a first demo but for the proper game you need to make sure that it is easier to see what an obstacle does by its visuals and to never use the same sprites for different objects (the two different buttons types and the one way platform didn’t look like one to me.)