If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
If you loved the Monster Constructor game you have to try Monster Constructor 2. Of all the truck games this one is packed with even more complex building tasks. This time you take a factory from its foundation up, to delivering the furniture at the warehouse.
Use the up and down arrow keys to drive your vehicles, use x for the crane to take and z to let go, the arrow keys to either move the magnet up or down left or right,left and right arrow key to move the machine hand and ctrl for it to grab ,use z for the tractor bucket to function, ctrl for the weighting machine to fold.