Pacman City: Turning "Dodge the Ghosts" into Timed Route Planning

Pacman City: Turning "Dodge the Ghosts" into Timed Route Planning

The Essence in One Sentence

Pacman City looks like a classic Pac-Man clone, but it actually reshapes the dodge-and-avoid archetype into a timed score-attack problem: within 120 seconds, the player constantly trades off "push progress by eating dots" against "stay alive by dodging ghosts" — and the power pellet's 8-second role reversal is the only rhythm switch in the game. When to take it, and where to hunt afterwards, decides the score ceiling.

Behavior Loop

1. Observe: 323 dots cover the maze at the start; 4 ghosts (red / cyan / pink / orange) patrol the streets; the HUD shows score, lives and the countdown in real time.
2. Plan a route: pick a line that chains dots without running into a ghost's patrol path — this is where the game's puzzle flavor comes from.
3. Execute: steer Pacman with the arrow keys or the on-screen joystick at bottom-left; dots are eaten automatically on contact, +10 each.
4. Power reversal: eat a golden power pellet in a corner for +50 and 8 seconds of power mode, during which ghosts can be eaten for +200 each — the highest single score in the game.
5. Back to dodging: when power mode ends, avoidance resumes; colliding with a ghost in normal mode costs 1 of 3 lives.
6. Settle and restart: when the 120-second countdown hits zero or lives run out, the result screen offers "restart" (a full data reset) or "back to menu".

Primitive Annotations

• SetDirection(dx, dy) – joystick / arrow-key input, converted into Pacman's heading
• EatDot(+10) – eat a dot on contact, add score, and check level completion
• EnterPowerMode(8s) – eat a power pellet: roles reverse, +50 points
• EatGhost(+200) – collide with a ghost during power mode for the top single score
• CollideGhost() – collide with a ghost in normal mode: lose 1 life and reset position
• Tick(-1s) – the countdown fires every second; reaching zero ends the run
• Reset(score/lives/time) – restart restores every value to its initial state

Parameter Cheat Sheet

| Parameter | Meaning | Default | Unit | |------|------|--------|------| | timeRemaining | Time limit per run | 120 | seconds | | lives | Starting lives | 3 | lives | | dotScore | Score per dot | 10 | points | | powerupScore | Score per power pellet | 50 | points | | ghostScore | Score per ghost eaten | 200 | points | | powerTime | Power mode duration | 8 | seconds | | pacmanSpeed | Pacman movement speed | 180 | px/s | | pacmanSize | Pacman radius | 16 | px | | dotsTotal | Total dots on the map | 323 | dots | | enemyCount | Ghosts on the field | 4 | ghosts |

Design Trade-offs

1. A 120-second hard limit instead of "until the maze is clean": in a pure eat-everything mode, pressure comes only from ghosts. A hard countdown makes "greed" and "survival" mutually exclusive at every moment, compressing the dodge archetype into score attack — and a short run makes the result screen's "restart" almost free to tap.
2. An 8-second power window: the reversal is deliberately short. Inside the window, players charge at the very ghosts they were fleeing seconds ago; emotion swings from tension to release and back — the strongest flow oscillation this game has. A longer window would dilute it.
3. A 10 / 50 / 200 score gradient: reward is strictly aligned with risk. Dots are steady income, the pellet is the rhythm switch, and eating ghosts is high-risk high-reward — nudging players to plan routes like "swing by the pellet, then cut the ghost off on the way back".
4. Dual input: joystick + keyboard: the virtual joystick serves touch screens, arrow keys serve desktop. One set of gameplay logic covers both device classes, with the input layer fully decoupled from gameplay.
5. 4 ghosts on the field: just enough to form moving blockades on the maze's arterial streets without sealing every route — combined with 3 lives of tolerance, beginners survive while veterans stay pressured.

Implementation Notes

• Thin rules, thick modules: the four states boot → menu → gameplay → result migrate on events (boot.complete / game.start / game.over / game.restart / game.menu); the rule layer only reads/writes data and forwards events, never touching rendering.
• Core module `core/pacman-city`: owns maze data, dot layout, ghost AI and collision detection, exposing four actions — reset / setDirection / checkLevelComplete / handlePlayerDeath; clearing all dots advances the level.
• Scene-private renderer: __OV.Games.PacmanCity.Game draws the city maze, Pacman, ghosts, dots and HUD in PIXI, takes over joystick and keyboard input, and emits pacman.move to the kernel.
• Timing sinks into the rule chain: game.tick fires every second; a rule writes remaining into timeRemaining, and at ≤0 it sets isGameActive=false and emits game.over, which the result screen renders.
• Zero custom UI code: button binding on the menu and result screens is handled by the generic common-ui module, and the boot scene auto-advances to the menu.

A playable demo of this game is embedded at the end of this article: steer with arrow keys or the joystick, and see if you can double your score with two well-timed power reversals within 120 seconds.