Roblox Pacman

Building a Proper Roblox Pacman Clone

Most people who try to build a Pacman-style game on Roblox don't realize how much work the AI pathfinding actually is. The ghost system in the original Arcade game isn't just random movement — each ghost has a different target tile and decision-making logic that determines where it goes at every intersection. Getting this right is what separates a fun game from something that feels broken after ten minutes of play. I spent about three weeks building my version from scratch after buying a free model off the toolbox that was supposed to be a complete Pacman clone. It wasn't. The ghosts just walked into walls and the score system didn't work past level two. I tore it apart and rebuilt the core loop using Signal-based pathfinding instead of the simple DistanceTo approach most tutorials recommend.

Why Roblox Pacman AI Pathfinding Usually Breaks

The standard approach people use is running a Raycast or checking the distance to the player every frame and moving toward them. This creates the "chasing" behavior you see in cheap clones, but it produces terrible results because ghosts will phase through walls trying to find the shortest path. The real solution uses A* pathfinding with a grid system. You need to convert your maze into a 2D array where each cell represents walkable or non-walkable space. I made my grid 28 by 31 tiles to match the original layout proportions. Once you have that grid, each ghost runs its own A* search every time it reaches an intersection, not every frame. Running it every frame destroys performance and causes jittery movement. Here is the specific problem I hit that took me days to figure out. When two ghosts are navigating the same intersection and both recalculate their paths simultaneously, they end up stacking on the same tile and soft-locking because neither can move forward. The workaround I used was implementing a simple timestamp system where each ghost locks its chosen path for 0.3 seconds after calculation. If another ghost tries to recalculate during that window, it reuses its previous path instead. This eliminated the stacking issue entirely.

The power pellets and scatter mode switching also need careful timing. The original game alternates between chase and scatter modes on a timer — roughly 7 seconds chase then 3 seconds scatter. If you don't implement this, ghosts become relentless and the game becomes unwinnable past level four. I found that simply adjusting the chase target based on the current mode (chase targets the player, scatter targets each ghost's home corner) was enough, but the transition needs to happen on exact intervals or players will notice the rhythm breaking.

What Most Tutorials Leave Out

The movement interpolation is probably the most overlooked piece. When a ghost or Pacman moves tile by tile, the raw position jumps from one integer coordinate to the next. You need to lerp the visual position between tiles over a set duration — usually 0.15 to 0.2 seconds depending on your grid size. Without interpolation, the game looks janky and the collision detection becomes unreliable because objects are never actually "between" tiles. Another thing nobody mentions is the death animation timing. If you trigger the win or lose condition the exact frame Pacman collides with a ghost, the player has zero reaction time and it feels unfair. I added a half-second grace period where the ghost continues its movement animation while Pacman plays a death tween, giving players a moment to process what happened before the screen transitions. This small change made the game feel significantly more polished.

For the Roblox Pacman market, the bigger concern is performance on lower-end devices. My initial build ran at 30 FPS on a first-generation iPad because I was doing pathfinding recalculations on the server every single frame for all four ghosts. Moving the pathfinding to the client and only sending position updates to the server dropped the framerate to a stable 60. The tradeoff is that speedhackers become possible, but for a casual arcade clone that isn't really a competitive concern.

Where This Approach Fails Completely

If you want true multilayer maze navigation with vertical movement or teleport tunnels that cross map boundaries, the 2D grid approach gets complicated fast. I ran into this when trying to add a second floor to my maze. The pathfinding algorithm still worked but the grid representation needed to account for elevation, which meant storing a 3D array and modifying the A* cost function to penalize stair usage. It added about two days of work for a feature that most players wouldn't notice anyway. You also cannot use this method if you plan to have dynamic maze generation. The grid has to be predefined and static for the pathfinding to remain reliable. If the walls move or change each level, you would need a completely different approach like navigation meshes or waypoint systems, and those are significantly more complex to implement correctly.

The source code for the grid-based A* implementation I ended up using is publicly available on GitHub under a creative commons license if you want to examine the actual Lua code rather than reading about it. The module is about 200 lines and handles path caching, path interpolation, and ghost mode switching. Building this from scratch without understanding the underlying pathfinding concepts will take most people a full week of debugging alone.