I LOVE it!
The mechanic is some simple, yet so interesting. Every time I figured out the solution, it felt so satisfying ; I could play puzzle games like this one for hours.
Only thing I wondered: is the fact you can't link the objects when only one of them is falling intentional? It feels like it should be possible to do so to stop a box mid-air, but maybe that's just me. This small detail alone won't make me like the game any less.
Excellent job!