The wall placement system was really neat. Nice job getting the different pieces to connect so seamlessly. The game itself was kind of confusing. Since I couldn't get an idea on where the enemy was spawning, I had trouble building a wall to prevent him from getting the treasure. Maybe split the game up into multiple, smaller levels with a clear start and end goal? I could see this turning into a cool 'complete the railroad as the train is moving along the tracks' type of game.