Shooting Game II — Scratch L2 Lesson 10

Learnt28 min · friction as a setting, health per clone, hearts
Basic24 min · build the real game
Challenge 1–327 min · tune it, toughen it, lose it
Extrabonus · design four weapons

WHAT IT SHOULD LOOK LIKE

Today the draft becomes a game. The big ones take six shots, the hearts run out, and for the first time in this arc you can lose.

holding on

not

panels run left to right

Review — the draft 5 min

The crosshair follows the mouse; the player points at it.
point towards [mouse-pointer v] runs once, when the bullet is born.
The player makes the bullet clone, so bullets do not clone each other.

Quick-fire

Two zombie clones are on screen. You set a variable called hp to 6. What happened to the other clone’s hp?

Reveal the answer

It depends. If hp is “for all sprites”, they share one number and you just changed both. If it is “for this sprite only”, each clone has its own. Today you find out why that matters.

Today’s Topic 3 min

Friction as a setting you can tune
Splitting setup from control
A variable that belongs to one clone
Tough enemies
Lives, hearts, and losing

Learning outcome

By the end of this lesson you will be able to:

Change how a game feels by changing one named number.
Give every clone its own health.
Show lives on screen and end the game when they run out.

Learnt — a game you can lose 28 min

Friction with a name

Your car had set [speed v] to ((speed) * (0.9)). That 0.9 is hiding a good idea. Give it a name:


set [friction v] to (0.1)
set [push v] to (0.9)

Two settings at the top of the setup, where you can find them.


set [vx v] to ((vx) * ((1) - (friction)))
set [vy v] to ((vy) * ((1) - (friction)))

Friction 0.1 means “lose a tenth of your speed every loop”. It reads as one sentence.

Now try 0.02 and then 0.4. One is ice; the other is mud. You did not touch the movement code once.

WHAT IT SHOULD LOOK LIKE

Friction stops being a number typed into a block and becomes a setting with a name. One value changes how the whole game handles.

friction 0.02 — ice

friction 0.4 — mud

panels run left to right

Runs here in the page. Nothing to install.

Click the Stage, then W A S D. Change the friction monitor by right-clicking the value, or edit the set block, and feel the difference straight away.

A variable that belongs to one clone

When you make a variable, Scratch asks you a question you have always ignored: for all sprites or for this sprite only?

For all sprites — one number, shared by everything. Your (score) should be this.
For this sprite only — every clone gets its own copy. Your (hp) must be this.

Make (hp) the second kind, and one script can run twenty zombies each with their own health.

WHAT IT SHOULD LOOK LIKE

One sprite, one script — but each clone keeps its own hp. That is what “for this sprite only” means, and it is why one zombie can be tougher than the next.

two clones, two healths

after three shots each

panels run left to right

Two kinds of zombie


when I start as a clone
if <(pick random (1) to (3)) = (1)> then
  set [hp v] to (6)
  set size to (75) %
else
  set [hp v] to (3)
  set size to (55) %
end
show

One in three is the big one. Bigger on screen too, so the player can see what is coming.


if <touching [Bullet v]?> then
  change [hp v] by (-1)
  switch costume to [skeleton-b v]
  wait (0.12) seconds
  switch costume to [skeleton-a v]
  if <(hp) < (1)> then
    change [score v] by (1)
    delete this clone
  end
end

The flash is not decoration. Without it the player cannot tell a hit from a miss, and a six-life zombie feels broken.

Runs here in the page. Nothing to install.

Shoot everything. The small ones drop in three; the big ones flash three more times and keep coming. Watch how differently the game plays.

They come for you

Last lesson the zombies walked straight across. Now they aim at you, every step:


point towards [Human v]
move (1.1) steps

Two blocks and the game gets much harder. Moving away no longer makes you safe — it just buys time.

WHAT IT SHOULD LOOK LIKE

Last lesson they walked in a straight line. Now they point at you first — so moving does not make you safe, it just buys time.

you stand high

you move low

panels run left to right

Three lives

A (lives) variable, and hearts drawn the way you drew digits in Lesson 4:


when flag clicked
hide
set [lives v] to (3)
forever
  if <(lives) > (0)> then
    go to x: (-205) y: (155)
    create clone of [myself v]
  end
  if <(lives) > (1)> then
    go to x: (-172) y: (155)
    create clone of [myself v]
  end
  if <(lives) > (2)> then
    go to x: (-139) y: (155)
    create clone of [myself v]
  end
end

One heart sprite. Each clone shows for 0.03 seconds and deletes itself, so the row always matches the number.

And a zombie that reaches you costs one:


if <touching [Human v]?> then
  if <(lives) > (0)> then
    change [lives v] by (-1)
  end
  delete this clone
end

The inner check matters: two zombies arriving together would otherwise take you to −1.

WHAT IT SHOULD LOOK LIKE

Three hearts, drawn exactly as Lesson 4 drew its digits: clones made in a forever loop, each living 0.03 seconds.

lives = 3

lives = 1

panels run left to right

Runs here in the page. Nothing to install.

No shooting in this one — just run. Every zombie that reaches you takes a heart, and at zero the game ends.

Losing needs one sprite watching. A referee waits until <(lives) < (1)>, broadcasts Over so the clones tidy themselves away, shows YOU LOSE, and then stop [all v].

Basic — build the real game 24 min

Open last lesson’s draft. Six sprites when you are done: Human, Aim, Bullet, Zombie, Heart, Referee.

Step 1 — split the human

Move the position, size and rotation style into a setup stack that ends with broadcast [Control v]. Put the forever loop on when I receive [Control v].

Step 2 — the two settings

(friction) and (push), set in the setup and used in the loop.

Step 3 — hp, for this sprite only

Make it, and check the box. Then the two-kinds if / else in when I start as a clone.

Step 4 — they aim at you

point towards [Human v] at the top of the walking loop, and set rotation style [left-right v] so they stay the right way up.

Step 5 — hearts

The heart sprite and its clone script.

Step 6 — losing

The referee, the Over broadcast, and YOU LOSE.

Step 7 — play three games

If you never lose, the zombies are too slow. If you always lose, they are too fast.

All the zombies die together.

(hp) is “for all sprites” — they are sharing one number. Make a new variable with “for this sprite only” ticked.

One bullet takes off six lives at once.

The touching check runs every frame while they overlap. The wait (0.12) seconds is what stops it — and the bullet should delete itself on contact too.

Lives go to −2.

Several zombies reached you in the same instant. Wrap the subtraction in if <(lives) > (0)> then.

YOU LOSE appears but the zombies keep walking.

Broadcast Over before you stop anything, and give the zombie a when I receive [Over v] → delete this clone.

CHALLENGE 1 · L2-10-M1🪙 30 Adcoins7 min

Tune the feel

(friction) and (push) are named settings, not numbers buried in blocks.
Setup and control are separate stacks.
You have tried at least three different friction values and chosen one.

Done when: you can make the player feel like ice or like mud by changing one number, and you can say which you chose and why.

CHALLENGE 2 · L2-10-M2🪙 50 Adcoins10 min

Tougher enemies

(hp) is for this sprite only.
Two kinds: a normal one and a big one that takes twice the shooting.
You can see when a hit lands.
They walk towards you, not past you.

WHAT IT SHOULD LOOK LIKE

Challenge 2 — the big one takes twice as much stopping, and it looks like it should.

one of each

Done when: a big and a small zombie are on screen together, you shoot the small one three times and it dies, and the big one is still coming after four.

Teacher note

Have them build it with hp “for all sprites” first and watch every zombie on screen die from one bullet. Ten seconds of that explains the checkbox better than any description, and it is the first time in the course that the choice has ever mattered.

CHALLENGE 3 · L2-10-M3🪙 70 Adcoins10 min

A game you can lose

The deck’s mission — the first version that is really a game.

Three lives, shown as hearts.
A zombie that reaches you costs one.
At zero, everything stops and the game says so.
Your score is still on screen at the end.

WHAT IT SHOULD LOOK LIKE

Challenge 3 — a game you can actually lose.

the last heart

game over

panels run left to right

Done when: you can play until you lose, see your score on the game-over screen, and start again with the green flag.

Teacher reveal — is it fun?

This is the first lesson where the answer might be no, and that is worth saying out loud. A game that is too easy is boring; too hard and nobody plays twice. The numbers to turn are the spawn wait, the zombie speed and the number of lives.

Ask each pupil to hand their game to the person next to them and watch without speaking. Where the other person struggles is the answer.

Runs here in the page. Nothing to install.

Zombie Defence, playable. W A S D to move, mouse to aim, click to shoot. Three hearts — see how high you can score before they are gone.

EXTRA MISSION · L2-10-MX🪙 100 Adcoinsbonus · needed next lesson

Design four weapons

Next lesson your player gets weapons. A weapon is not a picture — it is a set of numbers.

Damage — how much health it takes off
Fire rate — how long between shots
Ammo — how many before reloading
Reload — how long that takes

WHAT IT SHOULD LOOK LIKE

Extra Mission — four weapons on paper, ready to build next lesson.

the plan

Summary 5 min

Give your numbers names. A setting you can find is a setting you will tune.
For this sprite only gives every clone its own copy of a variable. That is how one script runs twenty enemies with different health.
Show the player when a hit lands, or they will think it did not.
point towards [Human v] turns a walker into a hunter.
A game becomes a game when you can lose it.

Friction: How fast speed leaks away. Higher means it stops sooner.
hp: Health points — how many hits something takes.
For this sprite only: A variable each clone owns separately.
Game over: Everything stops, and the player is told why.

Hand in

Share your game and send the link to your teacher, with your table of four weapons. Next lesson you build them.

Learnt28 min · friction as a setting, health per clone, hearts
Basic24 min · build the real game
Challenge 1–327 min · tune it, toughen it, lose it
Extrabonus · design four weapons

WHAT IT SHOULD LOOK LIKE

Today the draft becomes a game. The big ones take six shots, the hearts run out, and for the first time in this arc you can lose.

holding on

not

panels run left to right

Review — the draft 5 min

The crosshair follows the mouse; the player points at it.
point towards [mouse-pointer v] runs once, when the bullet is born.
The player makes the bullet clone, so bullets do not clone each other.

Quick-fire

Two zombie clones are on screen. You set a variable called hp to 6. What happened to the other clone’s hp?

Reveal the answer

It depends. If hp is “for all sprites”, they share one number and you just changed both. If it is “for this sprite only”, each clone has its own. Today you find out why that matters.

Today’s Topic 3 min

Friction as a setting you can tune
Splitting setup from control
A variable that belongs to one clone
Tough enemies
Lives, hearts, and losing

Learning outcome

By the end of this lesson you will be able to:

Change how a game feels by changing one named number.
Give every clone its own health.
Show lives on screen and end the game when they run out.

Learnt — a game you can lose 28 min

Friction with a name

Your car had set [speed v] to ((speed) * (0.9)). That 0.9 is hiding a good idea. Give it a name:


set [friction v] to (0.1)
set [push v] to (0.9)

Two settings at the top of the setup, where you can find them.


set [vx v] to ((vx) * ((1) - (friction)))
set [vy v] to ((vy) * ((1) - (friction)))

Friction 0.1 means “lose a tenth of your speed every loop”. It reads as one sentence.

Now try 0.02 and then 0.4. One is ice; the other is mud. You did not touch the movement code once.

WHAT IT SHOULD LOOK LIKE

Friction stops being a number typed into a block and becomes a setting with a name. One value changes how the whole game handles.

friction 0.02 — ice

friction 0.4 — mud

panels run left to right

Runs here in the page. Nothing to install.

Click the Stage, then W A S D. Change the friction monitor by right-clicking the value, or edit the set block, and feel the difference straight away.

A variable that belongs to one clone

When you make a variable, Scratch asks you a question you have always ignored: for all sprites or for this sprite only?

For all sprites — one number, shared by everything. Your (score) should be this.
For this sprite only — every clone gets its own copy. Your (hp) must be this.

Make (hp) the second kind, and one script can run twenty zombies each with their own health.

WHAT IT SHOULD LOOK LIKE

One sprite, one script — but each clone keeps its own hp. That is what “for this sprite only” means, and it is why one zombie can be tougher than the next.

two clones, two healths

after three shots each

panels run left to right

Two kinds of zombie


when I start as a clone
if <(pick random (1) to (3)) = (1)> then
  set [hp v] to (6)
  set size to (75) %
else
  set [hp v] to (3)
  set size to (55) %
end
show

One in three is the big one. Bigger on screen too, so the player can see what is coming.


if <touching [Bullet v]?> then
  change [hp v] by (-1)
  switch costume to [skeleton-b v]
  wait (0.12) seconds
  switch costume to [skeleton-a v]
  if <(hp) < (1)> then
    change [score v] by (1)
    delete this clone
  end
end

The flash is not decoration. Without it the player cannot tell a hit from a miss, and a six-life zombie feels broken.

Runs here in the page. Nothing to install.

Shoot everything. The small ones drop in three; the big ones flash three more times and keep coming. Watch how differently the game plays.

They come for you

Last lesson the zombies walked straight across. Now they aim at you, every step:


point towards [Human v]
move (1.1) steps

Two blocks and the game gets much harder. Moving away no longer makes you safe — it just buys time.

WHAT IT SHOULD LOOK LIKE

Last lesson they walked in a straight line. Now they point at you first — so moving does not make you safe, it just buys time.

you stand high

you move low

panels run left to right

Three lives

A (lives) variable, and hearts drawn the way you drew digits in Lesson 4:


when flag clicked
hide
set [lives v] to (3)
forever
  if <(lives) > (0)> then
    go to x: (-205) y: (155)
    create clone of [myself v]
  end
  if <(lives) > (1)> then
    go to x: (-172) y: (155)
    create clone of [myself v]
  end
  if <(lives) > (2)> then
    go to x: (-139) y: (155)
    create clone of [myself v]
  end
end

One heart sprite. Each clone shows for 0.03 seconds and deletes itself, so the row always matches the number.

And a zombie that reaches you costs one:


if <touching [Human v]?> then
  if <(lives) > (0)> then
    change [lives v] by (-1)
  end
  delete this clone
end

The inner check matters: two zombies arriving together would otherwise take you to −1.

WHAT IT SHOULD LOOK LIKE

Three hearts, drawn exactly as Lesson 4 drew its digits: clones made in a forever loop, each living 0.03 seconds.

lives = 3

lives = 1

panels run left to right

Runs here in the page. Nothing to install.

No shooting in this one — just run. Every zombie that reaches you takes a heart, and at zero the game ends.

Losing needs one sprite watching. A referee waits until <(lives) < (1)>, broadcasts Over so the clones tidy themselves away, shows YOU LOSE, and then stop [all v].

Basic — build the real game 24 min

Open last lesson’s draft. Six sprites when you are done: Human, Aim, Bullet, Zombie, Heart, Referee.

Step 1 — split the human

Move the position, size and rotation style into a setup stack that ends with broadcast [Control v]. Put the forever loop on when I receive [Control v].

Step 2 — the two settings

(friction) and (push), set in the setup and used in the loop.

Step 3 — hp, for this sprite only

Make it, and check the box. Then the two-kinds if / else in when I start as a clone.

Step 4 — they aim at you

point towards [Human v] at the top of the walking loop, and set rotation style [left-right v] so they stay the right way up.

Step 5 — hearts

The heart sprite and its clone script.

Step 6 — losing

The referee, the Over broadcast, and YOU LOSE.

Step 7 — play three games

If you never lose, the zombies are too slow. If you always lose, they are too fast.

All the zombies die together.

(hp) is “for all sprites” — they are sharing one number. Make a new variable with “for this sprite only” ticked.

One bullet takes off six lives at once.

The touching check runs every frame while they overlap. The wait (0.12) seconds is what stops it — and the bullet should delete itself on contact too.

Lives go to −2.

Several zombies reached you in the same instant. Wrap the subtraction in if <(lives) > (0)> then.

YOU LOSE appears but the zombies keep walking.

Broadcast Over before you stop anything, and give the zombie a when I receive [Over v] → delete this clone.

CHALLENGE 1 · L2-10-M1🪙 30 Adcoins7 min

Tune the feel

(friction) and (push) are named settings, not numbers buried in blocks.
Setup and control are separate stacks.
You have tried at least three different friction values and chosen one.

Done when: you can make the player feel like ice or like mud by changing one number, and you can say which you chose and why.

CHALLENGE 2 · L2-10-M2🪙 50 Adcoins10 min

Tougher enemies

(hp) is for this sprite only.
Two kinds: a normal one and a big one that takes twice the shooting.
You can see when a hit lands.
They walk towards you, not past you.

WHAT IT SHOULD LOOK LIKE

Challenge 2 — the big one takes twice as much stopping, and it looks like it should.

one of each

Done when: a big and a small zombie are on screen together, you shoot the small one three times and it dies, and the big one is still coming after four.

Teacher note

CHALLENGE 3 · L2-10-M3🪙 70 Adcoins10 min

A game you can lose

The deck’s mission — the first version that is really a game.

Three lives, shown as hearts.
A zombie that reaches you costs one.
At zero, everything stops and the game says so.
Your score is still on screen at the end.

WHAT IT SHOULD LOOK LIKE

Challenge 3 — a game you can actually lose.

the last heart

game over

panels run left to right

Done when: you can play until you lose, see your score on the game-over screen, and start again with the green flag.

Teacher reveal — is it fun?

Ask each pupil to hand their game to the person next to them and watch without speaking. Where the other person struggles is the answer.

Runs here in the page. Nothing to install.

Zombie Defence, playable. W A S D to move, mouse to aim, click to shoot. Three hearts — see how high you can score before they are gone.

EXTRA MISSION · L2-10-MX🪙 100 Adcoinsbonus · needed next lesson

Design four weapons

Next lesson your player gets weapons. A weapon is not a picture — it is a set of numbers.

Damage — how much health it takes off
Fire rate — how long between shots
Ammo — how many before reloading
Reload — how long that takes

WHAT IT SHOULD LOOK LIKE

Extra Mission — four weapons on paper, ready to build next lesson.

the plan

Summary 5 min

Give your numbers names. A setting you can find is a setting you will tune.
For this sprite only gives every clone its own copy of a variable. That is how one script runs twenty enemies with different health.
Show the player when a hit lands, or they will think it did not.
point towards [Human v] turns a walker into a hunter.
A game becomes a game when you can lose it.

Friction: How fast speed leaks away. Higher means it stops sooner.
hp: Health points — how many hits something takes.
For this sprite only: A variable each clone owns separately.
Game over: Everything stops, and the player is told why.

Hand in

Share your game and send the link to your teacher, with your table of four weapons. Next lesson you build them.