I lost my cube lol, I found a green one but took it to a door (I thought it was a key). When I tried to interact the cube went but door remained closed. I realize now from reading I wanted a pool not a door :).
At the high point for some reason I felt like I was in the movie Labyrinth and felt from the windows things were tantalizingly just out of reach. But then also got confused and decided to walk away from the challenge, so a plus and a minus.
If I was doing it I probably would use UI to show picked up cubes as when I grabbed it the visual and camera felt jarring.
Great first 3D game attempt!