The write txt isn't working because it is being started every frame.
In the "global events" event sheet on event 22 disable this action:
Chatbox: Set text to TextManipulator.GetRight(TextManipulator.GetLength-3)
and add a subevent to event 22:
+ MouseKeyboard: On key Space pressed
-> Chatbox: Write text TextManipulator.GetRight(TextManipulator.GetLength-3) at 1 letter per 1 milliseconds
Now drag event 24 right above event 20.
For the critical hit you could try something like this:
if random(101) less than or equal to Luck
then critical hit
A luck of 0 will never cause a critical hit.
A luck of 10 will be a %10 chance of a critical hit.
A luck of 100 will always be a critical hit.