I hope I only need to say this once: DO NOT BUILD AN ILLEGAL KEYLOGGER WITH THIS!!! Go anywhere. Look at what it is. Press space to save. Scroll down in the comments, press space and come back. Zoom out. Do whatever, and it WILL track you. Backpackable with credit. It runs really fast but is still pretty CPU intensive.
Myself, for finding out how to make sprites go offscreen, yes, I know other people have done this, but I found out how on my own. UPDATE: I used recursion to make sure that the precision still works. I did this because otherwise the SVG blurs which causes the touching mouse pointer to not work.