On level 18, I did (for fun) placed a couple of the "reverse" box and changed the arrow aim. Then the "reverse" box had a total of 4 arrows (red, green, blue and orange). My computer then stucked (the box hasn't any orders for blue and orange). I reloaded the page, and when I now click on lvl 18, and press start, it goes back to the menu! I can't play lvl 18 :(
If I start another level, I can't go back to the menu! Help please.