5.5 Building a runner game

You now have everything to build a runner game like Chrome Dino: a character that runs (or stays in place), obstacles that scroll from the right, and a jump or dodge to avoid them.

What we’re aiming for

• A player (e.g. a rect) on the left side of the screen.
• Obstacles (rects) that move from right to left.
• Jump (or duck): press Space (or Up) to jump; the player moves up then falls back (simple gravity).
• Collision: if the player hits an obstacle, game over. Optionally show “Game Over” and a way to restart.

Jump and simple gravity

Keep two variables: player_y or use player_rect.y, and a vertical speed (e.g. vy = 0). When the player presses jump, set vy = -15 (or another negative number). Each frame:

• Add gravity: vy += 0.8 (or similar).
• Update position: player_rect.y += vy.
• Ground: when the player hits the “ground” (e.g. a fixed y), set player_rect.y = ground_y and vy = 0 so they can’t fall through or jump again mid-air if you only allow one jump at a time.

Only allow jump when the player is on the ground (e.g. if player_rect.bottom >= ground_y and event.key == pygame.K_SPACE: vy = -15).

Spawning obstacles

• Keep a list of obstacle Rects.
• Each frame, move them left. If one goes off the left (rect.right < 0), remove it and (optionally) add a new one on the right at a random or fixed position.
• You can add a new obstacle every N frames or with a random chance, e.g. if random.randint(0, 60) == 0: obstacles.append(pygame.Rect(600, ground_y - height, width, height)).

Game over and restart

When player_rect.colliderect(obstacle):

• Set game_over = True.
• Stop updating the player and obstacles (or clear obstacles).
• Draw “Game Over” (e.g. with pygame.font or a big rect) and maybe “Press R to restart”.
• If the user presses R, reset: game_over = False, player back to start, clear obstacles, and continue the loop.

Checklist for your Chrome Dino–style game

1. Window, game loop, quit on close.
2. Player rect at a fixed x, moving up/down with jump and gravity.
3. Ground line (optional: draw a line or rect for the ground).
4. At least one obstacle (or many) moving left, respawning when off-screen.
5. Collision → game over.
6. (Optional) Score: increase every frame or every obstacle passed; show with text.
7. (Optional) Restart with a key.

Ideas to extend

• Different obstacle heights or speeds.
• Power-ups (e.g. double jump, shield).
• High score stored in a list or file.
• Sound with pygame.mixer (beep on jump or game over).

You’ve gone from no coding to a playable game — keep iterating and adding ideas.

---

Back to: Coding Club homepage