That good prototype. It gives HL2 vibes thanks to grabbing mechanics. In my opinion shapes should be more distinguishable. For the first time I was thinking why blue block does not trigger while there should be put green one. It should be changed like to something like roller or maybe sphere.
The mechanics are very nice. I like the shapes following you once you discover them. I hope you will develop this prototype more as it has potential to be a really good puzzle game.