Start, Play, Game Over

Your swarm of stars from last time rains forever. There’s no “Ready… go!”, no “Game over”, no “Play again?” — it just is. Every real game has those moments: a title screen, the actual playing, and the screen that pops up when you lose. Three different screens.

The trick the pros use is almost silly how simple it is: one variable that remembers which screen you’re on. We’ll call it state.

What’s a “state”?

A state is a word your game holds onto to remember what it’s doing right now. Ours will be one of three:

"start" — the title screen, waiting for you to begin
"play" — the game is on
"over" — you lost; offering a restart

Each frame, the game asks “which state am I in?” and does the right thing. That’s a state machine — a fancy name for a very plain if:

if state == "start":
    # show the title, wait for SPACE
elif state == "play":
    # run the actual game
elif state == "over":
    # show GAME OVER, wait for SPACE

SPACE is our magic button: it moves you from start into play, and later from over back into play.

A start screen

First, just two screens: a title, and a (still empty) game. Press SPACE to flip between them. Click the screen first so it hears your keys!

Your game — edit it, then press Run (click the screen, then use the arrow keys)

import pygame as pg

pg.init()
screen = pg.display.set_mode((400, 400))
clock = pg.time.Clock()
font = pg.font.SysFont("console", 22, True)

state = "start"

running = True
while running:
  clock.tick(60)
  for e in pg.event.get():
      if e.type == pg.QUIT:
          running = False
      if e.type == pg.KEYDOWN:
          if e.key == pg.K_SPACE and state == "start":
              state = "play"

  screen.fill((10, 14, 30))

  if state == "start":
      title = font.render("STAR CATCHER", True, (250, 220, 80))
      hint = font.render("Press SPACE to play", True, (255, 255, 255))
      screen.blit(title, (110, 150))
      screen.blit(hint, (90, 200))
  elif state == "play":
      msg = font.render("Playing!", True, (120, 220, 160))
      screen.blit(msg, (140, 180))

  pg.display.flip()

pg.quit()

Runs on Skulpt + pygame4skulpt — in your browser, nothing installed.

See it? The title sits there until you press SPACE — then state becomes "play" and the picture changes, because the drawing code asks if state == ... every single frame. The window didn’t reopen. Nothing reloaded. One variable flipped, and the whole screen changed.

Notice we only allow the SPACE jump when state == "start". That guard matters — soon SPACE will mean different things on different screens.

The whole game, with three states

Now the real thing. We drop last lesson’s swarm-of-stars game into the "play" state, add a basket you move with the arrows, and a lives count. Miss too many stars and state flips to "over". On the game-over screen, SPACE starts a fresh game.

Your game — edit it, then press Run (click the screen, then use the arrow keys)

import pygame as pg
import random

pg.init()
screen = pg.display.set_mode((400, 400))
pg.key.set_repeat(50, 25)
clock = pg.time.Clock()
font = pg.font.SysFont("console", 20, True)
big = pg.font.SysFont("console", 30, True)

state = "start"
stars = []
basket_x = 170
score = 0
lives = 3
timer = 0

def new_game():
  # reset everything for a fresh round
  return [], 170, 0, 3, 0

running = True
while running:
  clock.tick(60)
  for e in pg.event.get():
      if e.type == pg.QUIT:
          running = False
      if e.type == pg.KEYDOWN:
          if e.key == pg.K_SPACE:
              if state == "start" or state == "over":
                  stars, basket_x, score, lives, timer = new_game()
                  state = "play"
          if state == "play":
              if e.key == pg.K_LEFT:
                  basket_x = basket_x - 18
              if e.key == pg.K_RIGHT:
                  basket_x = basket_x + 18

  screen.fill((10, 14, 30))

  if state == "start":
      title = big.render("STAR CATCHER", True, (250, 220, 80))
      hint = font.render("Press SPACE to play", True, (255, 255, 255))
      screen.blit(title, (60, 150))
      screen.blit(hint, (90, 210))

  elif state == "play":
      # keep the basket on screen
      if basket_x < 0:
          basket_x = 0
      if basket_x > 340:
          basket_x = 340

      # harder as the score climbs: faster falling, more often
      speed = 3 + score // 5
      gap = 30 - score
      if gap < 8:
          gap = 8

      # spawn
      timer = timer + 1
      if timer >= gap:
          timer = 0
          stars.append({"x": random.randint(20, 380), "y": 0})

      # move
      for s in stars:
          s["y"] = s["y"] + speed

      # the basket as a rectangle
      basket = pg.Rect(basket_x, 360, 60, 16)

      # catch or miss: rebuild the swarm with only the survivors
      survivors = []
      for s in stars:
          star_rect = pg.Rect(s["x"] - 12, s["y"] - 12, 24, 24)
          if basket.colliderect(star_rect):
              score = score + 1          # caught!
          elif s["y"] >= 400:
              lives = lives - 1          # missed!
          else:
              survivors.append(s)        # still falling
      stars = survivors

      if lives <= 0:
          state = "over"

      # draw the swarm
      for s in stars:
          pg.draw.circle(screen, (250, 220, 80), (s["x"], s["y"]), 12)
      # draw the basket
      pg.draw.rect(screen, (120, 200, 255), basket)
      # draw the score and lives
      screen.blit(font.render("Score: " + str(score), True, (255, 255, 255)), (10, 10))
      screen.blit(font.render("Lives: " + str(lives), True, (255, 160, 160)), (290, 10))

  elif state == "over":
      over = big.render("GAME OVER", True, (255, 120, 120))
      sc = font.render("Score: " + str(score), True, (255, 255, 255))
      hint = font.render("Press SPACE to play again", True, (200, 200, 200))
      screen.blit(over, (90, 140))
      screen.blit(sc, (150, 195))
      screen.blit(hint, (50, 230))

  pg.display.flip()

pg.quit()

Runs on Skulpt + pygame4skulpt — in your browser, nothing installed.

That’s a whole game. A title, a round you can lose, a score, and a “play again.” Read the three if state == blocks — each is its own little world, and state decides which one runs this frame.

The difficulty ramp is two lines in the "play" block:

speed = 3 + score // 5   # every 5 points, stars fall faster
gap = 30 - score         # higher score = less wait between stars
if gap < 8:
    gap = 8              # ...but never insanely fast

The longer you survive, the faster and thicker the stars come. That climb is what keeps a game exciting instead of the same forever.

The one new idea here is restarting: when you press SPACE on the over screen, you reset everything — empty the stars list, put score and lives back, and set state = "play".

Try it 🎯

Edit the big program and Run after each change:

Easy mode: start with lives = 5 instead of 3.
Gentler ramp: change score // 5 to score // 10 so it speeds up half as fast.
Faster basket: change the 18 in both basket lines to 28.

Your mission 🚀

Add a fourth state: "paused". While playing, pressing the P key (pg.K_p) should flip state to "paused"; pressing P again flips it back to "play". In the "paused" state, draw a big “PAUSED” message and don’t move or spawn any stars — just show the frozen screen. (Hint: you’ll add an elif state == "paused": block for the drawing, and a pg.K_p check in the event loop that toggles between the two words.) This is the exact same state-machine idea — one more word your state can hold.

What you learned today

A state is a word your game remembers to know which screen it’s on ("start", "play", "over").
A state machine is just if state == "...": ... elif state == "...": — each block is one screen.
One key (SPACE) can mean different things in different states; guard it with the state you’re in.
Restarting is resetting your variables and setting state = "play" again.
Ramping difficulty with the score turns a toy into a game.

You now have every piece a small arcade game needs: a loop, shapes, input, a swarm, collisions, a score, and screens. Next time we put them all together into a brand-new game — you’ll pilot a ship and dodge a field of asteroids.

Next: Build-it: Dodge the Asteroids 🎮