You can use a global variable pretty much anytime you can type a number in the events mode. You can name the variables anything you want as long as construct isn't already using that name for something else. The above example would work if you used the name superCat. This would make it difficult to remember what it did, though.
It will also be important to reset the variable when you are done with the level or your bullets will always be speed 200.
but then how would construct no what im talking about is i just named any random variable? EG if i said variableExp.
How would construct no im talking about the EXP or points without it being somehow linked to that object ect