supaplex.eu

All your preferences stored on this computer. Therefore supaplex needs file system privileges (you should accept security warning on applet load). Btw, this is a quick way to start - you don't need to create account for that.

Applet is a component embedded into webpage (just like flash player). It is fixed size and linked to parent page, so if you close page or navigate away applet will be destroyed.

Java Web Start is not linked to the browser - this starts its own java application in a new window.

Nothing stored on your computer. Everything saved on the server, so you may continue your game from any computer on the net. But you need an account for that.