ok so you need to create an enemy sprite and give it an instance variable to represent its health. Then create a on touch, spawn lightning sprite at touch.x, touch.y. Give the lightning an animation, and have an event that destroys it at animation end. Add another event -> if lightning overlaps enemy, subtract x amount from enemy.health. You'll want that event to have a condition that triggers once while true. Last, you'll need a 'death' event. So, compare enemy instance variable health <= 0, destroy enemy. Add an event to spawn the enemies, and another to handle their motion and you should have a playable alpha.