If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Make Harry and Hermoine kiss each other secretly, avoiding the magical intervention created by Ron in the First Level, Ron and Dumbledore in the Second and Ron, Malfoy and Dumbledore in the Third Level. Either Do Not kiss when they appear or use the Magical Spells to make them disappear. Every Level will have only 3 Spells and once you use a spell, your intervener will appear a little later. To go to the Next level, complete the Kissing Loader.