maybe if((mouse_left == 1) && int(player.phaser) == 70) {}

but I'd use an easier thing just for testing, and just say if((mouse_left == 1) && player.phaser > 70){}. See if that works.

Also, like Bot said, I saw no reference to the beam_weapons function in the other code you posted. make sure you're calling it somewhere, or make sure it's running somehow. if you're not, that is your problem.

EDIT: never mind. I just saw your last post when you referenced on_mouse_left. So that's not the problem.