But seriously - System.exit() can do that??? Sheesh. It should simply throw an exception if you try to call it in an applet.
yup on ordinary applets it can't do that, but remember your using a signed applet, so no more sandbox, you can do pretty much anything
alternatively, if your ultratron jar doesn't need to go outside the sandbox, just don't sign it, and it won't be able to do that.
I will eventually get around to fixing a few of the niggles and updating the LWJGL release it's against but I'm too busy on Revenge of the Titans right now.
also don't forget to check out all the small things added to make lwjgl applet process more smoother and nicer.
e.g. like the new Display.setInitialBackground(r,g,b) method, where you can choose the background color (default - black) when Display creates a new lwjgl window, leads to a much smoother and seamless switch from AppletLoader to LWJGL Game. Theres even new Mouse methods for stuff like detecting mouse entering or leaving a lwjgl Display or even getting mouse coordinates outside the LWJGL Display.