This game is really addictive. At some point I just found myself dragging cards onto objects without even thinking about it. It was surprisingly satisfying. The sounds also help a lot. They make it really easy to get immersed in the game.
I ended up playing the whole thing in one go, trying to save those poor people from the end of the world xD
The only thing that confused me was the time rewards. It felt like putting simpler objects, like a tree, on the pyramid gave more time than the more advanced objects you unlock later. I expected it to be the opposite, so I wasn't sure if I missed something.
Other than that, I had a great time. This is the kind of game you can easily get hooked on for a while. Great job!