To make jumping, falling and throwing objects look realistic, you need to include real-world effects like gravity. This video shows you how to add gravity to a bouncing ball. Download the Scratch 2.0 code: simple_gravity
Friction
To make movement look realistic, you need to include real-world effects, like friction, in your Scratch games. This video shows you a simple way to include friction in the way your objects move. Download the Scratch 2.0 code: friction
Firing things
Lots of games have rockets and guns which the player uses to defeat their enemies. This video looks at a very simple way of adding shooting to your Scratch game. Download the Scratch 2.0 code: shooting
Positioning your sprites using x and y
This video covers how the x and y coordinates work when you are moving things around the stage. There are also a couple of tips for movement commands.