event.key == K_r:

[metulburr]

I presume K_r means the right arrow key, but nothing happens when I press the right arrow key.

Check out the pygame documentation. It is a go to must when your programming in pygame. Everything starts with K_ as it is keyboard. K_r is "r". K_RIGHT is right arrow.


As a side note: I think it is better and more adaptable to organize things in classes as opposed to nested functions.