Start a new Scratch project, and delete the cat sprite so that your project is empty. You can find the online Scratch editor at jumpto.cc/scratch-new.

For this project, you should have a ‘Project Resources’ folder, containing the background image you’ll need. Make sure that you can find this folder, and ask your club leader if you can’t find it.

Add the image ‘background.png’ as a new stage backdrop, or draw your own! If you’re drawing your own level, just make sure that the poles and the floors are different colours, and that there’s a door (or something similar) that your player has to reach. Here’s how your project should look:

Add a new sprite, which will be your character. It’s better if you choose a sprite with multiple costumes, so that you can make it look as though it’s walking.

Let’s use the arrow keys to move your character around. When the player presses the right arrow, you want your character to point right, move a few steps and change to the next costume:

    when flag clicked
    forever
        if <key [right arrow v] pressed? > then
            point in direction (90 v)
            move (3) steps
            next costume
        end
    end

Test out your character by clicking the flag and then holding down the right arrow key. Does your player move to the right? Does your character look like they are walking?

To move your character to the left, you’ll need to add another if block inside your forever loop, which moves your character to the left. Remember to test your new code, to make sure that it works!

To climb a pole, your character should move up slightly whenever the up arrow is pressed and they’re touching the correct colour. Add this code inside your character’s forever loop:

    if < <key [up arrow v] pressed?> and <touching color [#FFFF00]?> > then
        change y by (4)
    end

Test your character - can you climb the yellow poles and get to the end of your level?

You may have noticed that your character can walk off a platform into mid-air. Try to walk off of a platform and see what happens.

To fix this, let’s add gravity to your game. Create a new variable called gravity. You can hide this variable from your stage if you want to.

Add this new code block, which sets the gravity to a negative number, and then uses this to repeatedly change your character’s y-coordinate.

    when flag clicked
    set [gravity v] to [-4]
    forever
        change y by (gravity)
    end

Click the flag, and then drag your character to the top of the stage. What happens? Does the gravity work as you expected?

Gravity shouldn’t move your character through a platform or a pole! Add an if block to your code, so that the gravity only works when your character is in mid-air. The gravity code should now look like this:

    when flag clicked
    set [gravity v] to [-4]
    forever
        if < not < <touching color [#0000FF]?> or <touching color [#FFFF00]?> > > then
            change y by (gravity)
        end
    end

Test the gravity again. Does your character stop when they are on a platform or a pole? Can you walk off the edge of platforms to the level below?

Let’s also make your character jump when the player presses the space bar. One very easy way to do this is to move your character up a few times, using this code:

    when [space v] key pressed
    repeat (10)
        change y by (4)
    end

As gravity is constantly pushing your character down by 4 pixels, you need to choose a number greated than 4 in your change y by (4) block. Change this number until you’re happy with the height your character jumps.

If you test out this code, you’ll notice that it works, but the movement isn’t very smooth. To make jumping look smoother, you’ll need to move your character by smaller and smaller amounts, until they’re not jumping anymore.

To do this, create another variable called jump height. Again, you can hide this variable if you prefer.

Delete the jumping code you added to your character, and replace it with this code:

    when [space v] key pressed
    set [jump height v] to [8]
    repeat until < (jump height) = [0] >
        change y by (jump height)
        change [jump height v] by (-0.5)
    end

This code moves your character up by 8 pixels, then 7.5 pixels, then 7 pixels, and so on, until your character has finished jumping. This makes jumping look much smoother.

Change the starting value of your jump height variable and test it until you’re happy with the height your character jumps.