There's either an event outside of what you're showing interfering with you being able to play.
Or there's an object in the way of you being able to click it.
The information you are giving here should just work in my eyes, that's why a capx would help identify the problem.
It only goes to the game when your variable is 1, which it always should be when clicking on it.
You don't need a condition of "play = 1"
Try and see if it works if you disable that line with "D".