Workshop › Pac-Man-style Maze Chase › Step 20 of 42

The ghost walks

What we are doing

Every frame, after the player, advance each ghost with chooseGhost. One catch: if the player's move just cleared the maze, everyone was placed again, so the ghosts skip that frame.

```js
function update() {
  const startLevel = level
  advance(player, choosePlayer)
  if (level !== startLevel) return

  for (const g of ghosts) advance(g, chooseGhost)
}
```

What it means

• startLevel remembers the level before the player moves; a different level afterwards means a new maze was set up.
• The same advance moves the ghosts; only the choose function differs.

Your turn

Replace the body of update as shown.

Skills: The game loop, Game states

← A ghost never turns back The ghost hunts you →

All steps

1. The maze as text
2. The game loop
3. Draw the walls
4. A set of pellets
5. Draw the pellets
6. The player
7. Where can you walk?
8. What a mover remembers
9. One frame of movement
10. Move every frame
11. Turns you can press early
12. Glide between tiles
13. Turn back at once
14. Swipes on a phone
15. Eat the pellets
16. Show the score
17. Clear the maze
18. A red ghost
19. A ghost never turns back
20. The ghost walks
21. The ghost hunts you
22. Four ghosts in the house
23. One by one out of the house
24. Scatter or chase?
25. Every ghost to its corner
26. Pink cuts you off
27. Orange is shy
28. Cyan works with red
29. Wait for the first key
30. Tell the player to start
31. Three lives
32. Caught!
33. Game over
34. Play again
35. Frighten the ghosts
36. Power pellets work
37. Scared ghosts wander slowly
38. Eat a scared ghost
39. Blue, then flashing
40. Harder levels
41. A best score that lasts
42. Build it yourself: the slow tunnel