if you want to reset you can use either reset layout system expression or go to layout..
for resetting the local variables i think they reset automatically on restarting the layout
for resetting the global variables you can use before the go to layout or restart the layout expression ... the expression called reset global variables that will reset the variables to the default state of them.
but reseting the global variables wold cause issues like in the case of having highscores that needs to stay with the last values unless you save them in a localstorage or server, the data of highscores will be lost.