Loved it! you feel the portal vibe (a bit to much to be an "unique" game, but at least, you're using a good ground!)
This kind of mechanism seems new to me so I enjoyed it!
I think you can add a bit more feedback here and here (for example, why a cube can't pass by it s own color gate, ...)
Congrats for your game, you get something. Now it's time to make it shine!