I thought it was really intuitive to push the objects, as it was the only thing you could do. I also intended it to be like a puzzle game where you are suppose to figure it out yourself?
You can't predict what players will do, unless you guide them towards it, it's a nice idea to let players figure out things for themselves but: one thing that might be natural/obvious to you will not be the case for all. That is why I think the game would be better if you had indicators that you can push certain objects, etc. Even if it's just an outliner/highlighter -could be very subtle
A little bit hand-holding can be good, just don't hold their hands all the way through ;)