Creating some basic game objects, cloning them to populate your level, & making them movable.
Introduction to Behaviors, and using them to make your player character move around your level.
Animating your player sprite in the sprite editor, and playing the animation using behaviors.
Making your first level larger, and scrolling the viewable area by adding a Camera.
Giving your player some Health, and adding some dangerous objects to your level.
Adding some collectible items, sound effects, and music to your game.
Adding adding another level and switching between them. Using Switches & Message behaviors for more interesting game logic.
Giving your player a shooting star ability, and organizing your behavior logic using Bundles.