Great game. I don't read (i.e. i'm bad at reading, i just jumped straight in) so I didn't see that you can zoom out. Also, if the area is limited you can put a limit to how much the camera moves to the side. Something like if camera.position.x > ((farthest right pixel - camera.width)/2) -1 = ((farthest right pixel - width)/2) - 1 and then likewise for the left side, upside, and downside. I couldn't figure out how to get new turrets. Overall, excellent job creating a tower defense game.