Activity Checklist

• 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.

• Add the ‘stars’ backdrop and the ‘spaceship’ sprite to your project. Shrink the spaceship and move it near the bottom of the screen.

  

• Add code to move your spaceship to the left when the left arrow key is pressed. You’ll need to use these blocks:

      forever
          if <key [left arrow v] pressed?> then
              change x by (-4)
          end
      end

• Add code to move your spaceship to the right when the right arrow key is pressed.

• Test your project to see whether you can control your spaceship with the arrow keys.

Activity Checklist

• Add the ‘Lightning’ sprite from the Scratch library. Click the sprite’s costume and turn the lightning upside-down.

  

• When the game is started, the lightning should be hidden until the spaceship fires its laser cannons.

      when flag clicked
      hide

• Add the following code to the spaceship to create a new lightning bolt whenever the space key is pressed.

      when flag clicked
      forever
          if <key [space v] pressed?> then
              create clone of [Lightning v]
          end
      end

• Whenever a new clone is created, it should start in the same place as the spaceship, and then move up the stage until it touches the edge. Add the following code to the Lightning sprite:

      when I start as a clone
      go to [Spaceship v]
      show
      repeat until <touching [edge v] ?>
          change y by (10)
      end
      delete this clone

Note: We move the new clone to the spaceship while it is still hidden, before then showing it. This just looks nicer.

• Test your lightning, by pressing the space key.

Activity Checklist

• Create a new sprite from the ‘Hippo1’ image in the Scratch library.

  

• Set its rotation style to be left-right only, and add the following code to hide the sprite when the game starts:

      when flag clicked
      hide

• Create a new variable called speed, that is for the hippo sprite only.

  

  You’ll know if you’ve done this correctly because the variable will have the name of the sprite next to it, like this:

  

• The following code will create a new hippo every few seconds. The Stage is a good place for this code to live:

      when flag clicked
      forever
          wait (pick random (2) to (4)) secs
          create clone of [Hippo1 v]
      end

• When each hippo clone starts, make it move around the stage (at a random speed) until it gets hit by the lightning. Add this code to the hippo sprite:

      when I start as a clone
      set [speed v] to (pick random (2) to (4))
      go to x: (pick random (-220) to (220)) y: (150)
      show
      repeat until <touching [lightning v] ?>
          move (speed) steps
          turn right (pick random (-10) to (10)) degrees
          if on edge, bounce
      end
      delete this clone

• Test out your hippo code. You should see a new hippo clone appear every few seconds, each moving at its own speed.

  

• Test your laser cannon. If you hit a hippo, does it vanish?

• When a hippo touches your spaceship, we need to make the spaceship explode! To do this, first make sure that your spaceship has 2 costumes called ‘normal’ and ‘hit’.

  

  The spaceship’s ‘hit’ costume can be made by importing the ‘Sun’ image from the Scratch library, and using the ‘Color a shape’ tool to change its colour.

  

• Add this code to your spaceship, so that it switches costume whenever it collides with a flying hippo:

      when flag clicked
      forever
          switch costume to [normal v]
          wait until <touching [Hippo1 v]>?
          switch costume to [hit v]
          broadcast [hit v]
          wait (1) secs
      end

• Did you notice that you have broadcast a ‘hit’ message in the code above? You can use this message to make all of the hippos disappear when the spaceship is hit.

  Add this code to your hippo:

      when I receive [hit v]
      delete this clone

• Test out this code by starting a new game and colliding with a hippo.

  

Activity Checklist

• Firstly, make a new bat sprite that will move across the top of the stage forever. Remember to test out your code.

  

• If you look at the bat’s costumes, you’ll see that it already has 2:

  

  Use the next costume block to make the bat flap its wings as it moves.

• Create a new ‘Orange’ sprite from the Scratch library

  

• Add code to your bat, so that it creates a new orange clone every few seconds.

      when flag clicked
      forever
          wait (pick random (5) to (10)) secs
          create clone of [Orange v]
      end

• Click on your orange sprite, and add this code to make each orange clone drop down the stage from the bat towards the spaceship:

      when flag clicked
      hide
  
      when I start as a clone
      go to [Bat1 v]
      show
      repeat until <touching [edge v]?
          change y by (-4)
      end
      delete this clone
  
      when I receive [hit v]
      delete this clone

• In your spaceship sprite, you’ll need to modify your code so that you are hit if you touch a hippo or an orange:

      wait until < <touching [Hippo1 v]?> or <touching [Orange v]?>>

• Test your game. What happens if you get hit by a falling orange?

Activity Checklist

• If you haven’t already, create a new variable called lives. Your spaceship should start with 3 lives, and lose a life whenever it collides with an enemy. Your game should also stop when you run out of lives. If you need help, you can use the ‘Catch the Dots’ project to help you.

• Draw a new sprite called ‘Game Over’, using the text tool.

  

• On your stage, broadcast a game over message just before the game ends.

      broadcast [game over v] and wait

• Add this code to your ‘Game Over’ sprite, so that the message shows at the end of the game:

      when flag clicked
      hide
  
      when I receive [game over v]
      show

  Because you’ve used a broadcast [game over] and wait block on your stage, it will wait for the ‘Game Over’ sprite to be displayed before ending the game.

• Test your game. How many points can you score? Can you think of ways to improve your game if it is too easy or too hard?