While your students might not remember Galaga, they can now experience something similar with the new Moodle Quiz Mod, Quizventure. Quizventure is developed and maintained by John Okely and is now available in the Plugins Database.
What’s it do? Quizventure is a Moodle activity that loads multiple choice quiz questions from your courses item banks and serves them up to students space invaders style. To win students need to identify and shoot the correct answer. Seems like it could make those boring vocab quizzes that much more exciting.
Check it out at https://moodle.org/plugins/view.php?plugin=mod_quizgame