Oh, just a quick additional explanation—since I didn't get around to it earlier: the 'E' key toggles between build mode and adventure mode. In build mode, the mouse scroll wheel adjusts the height of the block being placed; blocks snap to others and solidify. If you make a mistake while building, you can right-click the misplaced block to remove it. You can build houses, bridges, or anything else. I had planned to create various levels—ranging from building barriers to constructing houses—but I didn't have enough time during this game jam session.
The story is also currently incomplete; the intended ending involved the child pressing the TV remote to watch an action-adventure movie, becoming engrossed in play, and drifting into a realm of imagination—perhaps a dream—only to wake up with the toy in hand upon "losing" the game.