I like the idea, but I wasn't able to get past the first puzzle. I managed to transfer over the gravity beam to the other blue box, but I couldn't reverse it with either R or the right mouse button. Maybe you could have added some in-game tutorial or more clear instructions to make sure the player learns the mechanics before introducing the puzzles.
I think the presentation looked clean and it really fit into the portal vibe, but but the bright light walls made it a bit hard to distinguish where a wall ended and a corridor began since it doesn't seem to be any dynamic shadows in the game.
Good job on managing to implement the gravity beam feature and make multiple puzzle levels in just 48 hours!