Purgatory Purgers: Version 1.5 Released!

Update Summary

  • Collecting 100% of the souls with Bob (the demon) is now possible!
  • Resolved clipping issues in the levels “Stilted Pond” and “Toad Hall.”
  • Gamepads, including PlayStation, Xbox, and Super Nintendo-style controllers, are now generally supported*. See the notes below for additional information.
  • Updated the Purgatory Purgers Manual to include gamepad button mappings

Special thanks to @ABitNosthalgic for suggesting that we make it possible to collect 100% of the souls with one character or another!

Gamepad/Controller Support Notes

*Most PC-compatible controllers with a Direction Pad (D-Pad), Start and Select buttons, and four face buttons should work. The game has been tested on the following devices:

  • Logitech F310
  • X-Box Elite Series 2 Wireless
  • Megafire 412-NO5 (generic PlayStation 2 Style Controller)
  • 8BitDo SN30 Pro (SNES-style controller)

@ABitNosthalgic reported that the Suily brand NES-style controllers did not work for him. While I haven’t tested this myself, the reviews seem to suggest that problems, particularly with the D-Pad, aren’t that uncommon.

Purgatory Purgers: Version 1.4 Released!

Update Summary

  • Resolved a bug (warning, spoilers!) that would destroy objects unintentionally when two blocks collided
  • Added a spawn/respawn animation and sound effect
  • Reworked the Passphrase mechanic (used to continue to a previously visited level) to display the Passphrase on the pause screen under the main menu as well as the Game Over screen.
  • Updated the Purgatory Purgers Game Manual to better describe the Continue/Passphrase mechanic and other menu features.

Special thanks to @ABitNosthalgic for catching the bug and Jason D for passphrase feedback!


Purgatory Purgers: Buggery

Warning: Spoilers Ahead!

This post discloses the locations of some of the secret rooms found within Purgatory Purgers. If you’d rather discover these surprises for yourself while playing the game, you may want to avoid reading further!

A Fresh Perspective

Players are often your best resource for identifying possible bugs, exploits, and missed opportunities (read: feature requests). The week Purgatory was released, I received a lot of feedback and, with it, fresh eyes to point out my mistakes.

I addressed what I could and tabled the rest, save for one elusive bug I could never pin down but appeared so infrequently that I couldn’t get a bead on it. Occasionally, an object or group of objects (e.g., a gem block, ethereal coins, etc.) would go missing from a room, and I couldn’t explain why nor duplicate the behavior. Unable to identify the culprit, coupled with the sporadic nature of the bug, I decided to leave well enough alone…

Recently, a new YouTube channel, “Back to the Past Gaming,” started a playthrough series for Purgatory Purgers. While watching ABitNosthaligic‘s playthrough of the fourth level of Purgatory Purgers, “Stilted Pond,” I was surprised to see that the secret room he discovered was empty:

He suggested it might have been an oversight, and while it’s certainly possible that I’d forgotten to populate the room, the problem was (unfortunately) not that simple… And so, after a 3-month hiatus, I decided to tear back into the code to under, once and for all, why this was happening!

First, Check the Obvious

Looking at the room layout in the GameMaker IDE, I could see the objects had been placed:

So why were they missing during his playthrough? I fired up the game, went straight to the offending level, and made a beeline for the secret room. Upon entering, there were the Ethereal Coins right where I expected them to be:

To try to duplicate the [unwanted] behavior, I did a normal playthrough, and lo behold, the coins were missing for me, too! Progress, at last! But why? What exactly was happening to the coins? Were they failing to render? Were they being destroyed?

So, to begin my troubleshooting, I added the following code to the “obj_oneup” object’s Draw GUI Event:

// Am I here?
draw_text(20,20,"I'm still here!")

Whenever you use custom draw code (e.g., draw_text), you must precede it with “draw_self(),” or the sprite won’t be drawn. The purpose of the draw_text message is to print the string “I’m still here!” in the upper left-hand corner to let me know that at least one instance of the object still exists on the map. Simply put, these two lines of code tell me that the object is both visible and present.

I saved my work, then launched the game, and upon entering the first level, I could see the message right where I expected it:

After collecting the Ethereal Coins, the message disappeared as expected. So, I continued playing until I reached the offending level (Stilted Pond), and after some experimentation, I was finally able to observe what was happening…

Next, Eliminate the Impossible

“When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”
– Sherlock Holmes, The Sign of Four

Whenever I pushed one block into another block, all of the Ethereal Coins in the current room were instantly destroyed. This was true, regardless of level, but I couldn’t yet understand why…

The way I coded movement for blocks, enemies, and the player in Purgatory Purgers was a modified version of my grid movement system, explained here and here. In short, here’s what happens when you “push” a block:

  1. An instance of an invisible 16x16px target object is created 32 pixels ahead.
  2. The block moves toward the target object.
  3. Upon collision, the target object is destroyed, and the block’s movement speed is set to zero, stopping it.

Because we’re using an Instance Variable, it has to be declared in the Create Event, e.g.:


This variable would later be defined in the Step Event whenever the block was moved, something to the effect of,


In the example above, “block_target” is the variable that refers to the Instance ID of the specific instance of the obj_block_target object we’re dealing with and nothing else! So when obj_block collides with the instance of obj_block_target that it created, i.e., “block_target,” only that instance should be destroyed, but somehow, the obj_oneup was being [mis]associated with “block_target.”

Block movement was one of the first features I coded, and later implementations used the place_meeting function in the End Step Event. So, simply recording it to do that fixed the issue.

I still don’t fully understand this, and after hours of troubleshooting, I am relieved that this was resolved. I have since posted the fix to itch.io as version 1.4.

Purgatory Purgers: Level Design

What Should a Level Look Like?

In my last post, I solved a major collaboration issue by figuring out how to export/import individual rooms in GameMaker Studio 2.

Since then, Eric and I have been creating levels to round out the game, and with a little over an hour’s worth of content, I’ve been looking at some of the larger levels to see which parts I can cull so that the game doesn’t get dull/outstay it’s welcome.

Level design is difficult to do well. Purgatory Purgers’ level elements can be broken down into a few different components:


At its heart, Purgatory Purgers is a puzzle-exploration game. Each level is a series of interconnected rooms of varying shapes and sizes and could include:

  • Gambits: Rooms with one or more dangerous enemies
  • Treasure Rooms: Filled with lost souls (the primary objective of the game/scoring system) and free lives
  • Puzzles: Moveable blocks, bridges, etc.
  • Secrets: Hidden rooms and passages marked by a small crack in the floor or an odd-looking bush.

These aren’t mutually exclusive and could be combined to form interesting and progressively more challenging areas.


A good level shouldn’t railroad the player down a specific route; instead, there should be 2-3 branching paths and reward players for exploration with additional lives and/or hidden shortcuts through the level.


To bring the Purgatory Purgers levels to life, I created lots of additional tiles to add flavor and mystery to each set of levels. Locked doors, sewer grates, pools of water, grass, grates, blood spatters, arcane symbols, and even emptiness in the later levels.

Putting It All Together

A good level combines all of the above to form a cohesive package; the level is:

  1. Good looking (i.e., makes good use of the available tileset and avoids excessive repetition)
  2. Intuitive to navigate (it doesn’t require a lot of backtracking)
  3. Sufficiently diverse in enemies, puzzles, and mechanics
  4. Above all, fun to play (read: sufficiently challenging, but not too difficult)

GameMaker Studio 2: Exporting/Importing Rooms


I’ve been looking for a way to allow another user to create rooms for my existing project using templates I’d created with consistent instance, tile, and background layers.

After my experiment with source control ended in disaster, I decided to shelf that for the time being and try a simpler approach:


  1. On PC1, I Exported the as-is project as a .yyz file (File > Export Project > YYZ) and then saved the file to a network share.
  2. On PC2, I downloaded the [MyProjectName].yyz file and Imported it (File > Import Project > Path\To\.yyz file).
  3. I updated the project on PC2 by creating a new room, and then I saved the project.
  4. I opened File Explorer on PC2 and browsed to the project’s rooms subfolder (i.e., C:\>Users\[MyUsername]\Documents\GameMakerStudio2\[MyProjectName]\rooms).
  5. I located the corresponding folder to the new room I’d created, then copied the room2.yy file back to the network share.
  6. Back on PC1, I created a subfolder in my project with an identical folder name and then copied the room2.yy file to that location.
  7. I opened GameMaker Studio 2, right-clicked in the Asset Browser, and selected “Add Existing“. After navigating to the room subfolder from the previous step, I selected the .yy file and clicked “Open.” Nothing happened!

At this point, the rooms list didn’t update with the new asset, nor did I receive an error.

The Missing Step

After opening the game’s project file (.yyp) in a text editor, I could see a list of resources, including rooms, along with their relative paths:

"resources": [

What I did not see was an entry for the new room I created, so I simply appended the list with the new room:

"resources": [

Towards the bottom of the list is the room order, which I also appended:

 "RoomOrderNodes": [

After saving and closing the text editor, I fired GMS2 back up, opened the project, and after an agonizing minute or so of loading, the project opened without error!

To my delight, there sat the imported room in the asset browser. I double-clicked it, and there it was:

Alternatives Considered

Someone on the official forums had suggested having Eric submit asset packs – I have no idea what that means exactly, but he seemed to suggest this was less than ideal.

Eric’s original levels were created in Tiled, and then I’d manually recreate them in GMS2, which was inefficient and very time-consuming; however, I’d heard that there were tools that could convert a Tiled map to a GMS2 .yy room resource file but couldn’t get it to work properly with my project. This is because our maps utilize multiple tile layers sandwiched between an instance layer (where the objects live) and the background layer. Most of these tools assume you are working for a single tile layer to another single tile layer, and none of the address how to get the room.yy file back into your project.

Caveats and Disclaimers

  • In order for this to work, all of the resources used in the room (i.e., objects, sprites, tilesets, etc.) must be present and unchanged in both the source and destination projects
  • GMS2 is known to not play nice with Cloud-synced project folders, so make neither system

Revisiting the Triple Threat

About ten years ago, I distilled video game development into three core skillsets (i.e., the triple threat):

  1. Art
  2. Music (and sound effects)
  3. Programming

I’ve always been interested in art (drawing, sculpting, and to a lesser extent, painting). I taught myself how to play simple melodies on a cheap Casio keyboard in my teens. I learned to use, repair and maintain personal computers in the early 90s out of necessity (I didn’t have much money, so my choices were to fix it or do without).

Eventually, I started entertaining the idea of combining my love of art, music, and computers to try my hand at making video games instead of just playing them. Thus began my journey of self-discovery.


I’d always been able to draw relatively well by hand. I lightly scribbled rough shapes, then fleshed them out with strong lines. As technology became more accessible, I’d digitize my art using a flatbed scanner.

I even purchased a digital camera and some clay in the early 2000s to sculpt models and photograph them from different angles in much the same fashion as Adrian Carmack did for DOOM. I could never get the hang of 3D modeling or translate these analog skills into digital media. In time, I abandoned that track in favor of pixel art.

At first, I was terrible at it. But by studying examples, watching tutorials, and practicing, I developed proficiency using Pyxel Edit. I started with a 16-color EGA palette, then later expanded this to the 52-color NES palette.

This has become my niche and primary medium for artwork creation. Tile sheets are relatively quick to make, which is important when you’re a one-man operation. There are 40 years of examples to draw upon for inspiration.


I’ve been writing music for almost 30 years on the Amega Module format, beginning with tunes written on Fast Tracker II using samples ripped from other people’s files. Later, I sampled some high-quality instruments – these were used in the publication of my first album.

Unfortunately, the songs and samples used were lost to time, but I still have a 20-year backlog of my previous work,  dating as far back as 1997, all written for games that existed only in my imagination.

These days, I use a Windows port called “Skale Tracker.” It’s based on FT2, can export to .WAV and .OGG formats, and supports up to 64 tracks (although I rarely need more than eight these days and write chip tunes with half that). I’ve mixed and mastered my exported works in Audacity and have been very satisfied with the results.


Programming has always been my biggest weakness. I’ve never been the kind of person who can read a book on a subject and put that knowledge into practice. At best, I can look at examples, then adapt those to my needs once I understand how.

Someone once told me that DOOM was programmed in C++ and that I could do likewise. I remember seeing a boxed copy of Borland Turbo C++ at the local Best Buy, retailing for $300. I remember thinking then that if only I had the money to buy it, I’d have everything I needed to program my own version of DOOM. I was woefully ignorant back then…

Many times over the years, I’d hoped to get around my limitations by using a game creation engine,  my first exposure to this was around 1995. I’d gotten ahold of the Pie in the Sky Software’s 3D Game Creation System for MSDOS.

It was a 2.5D game engine capable of creating games slightly beyond Wolfenstein 3D (floor and ceiling textures, angled walls) but fell short of DOOM (no height variable). While I had limited success designing very simple levels, I didn’t understand its limitations or advanced features and gave it up in frustration.

In my late teens to early 20s, I experimented with 3D Game Studio.

I could create primitive shapes, texture them, and use those objects as building blocks to create a castle out of modular pieces. I could render the map and fly through it, but I had no idea how to use its scripting language. I continued to toy with it for a couple of years, but again, I got discouraged as my imagination outpaced my ability.

In 2014, I picked up GameSalad, and created this website. I had no idea what I wanted to create, so I groped around aimlessly in the dark, bumping into bugs and lacking support.

At the time, GameSalad was primarily marketed to Mac users, and the Windows version lacked many core functions. By the time it caught up to the Mac version, they had stopped offering the Standard Edition for free and switched to a subscription model. I didn’t feel comfortable paying for something I wasn’t entirely sure I could learn to use, so I abandoned it and moved on.

I discovered Game Maker Studio in the spring of 2016. I teamed up with my old friend Eric, and we set out to learn the engine. Eric volunteered to do the programming, I would do everything else (artwork, music, design, documentation, project management).

In the early days, YouTube tutorials were our primary source of GMS programming information. Later, I would compare these to “let’s play” videos rather than proper lessons. Thankfully, I eventually discovered John Janetka’s Game Programming Course (GPC). This was a game changer for us (well, me anyway). While the second half of the lessons became disjointed, it was enough to see me through the creation and publishing of my first game.

Unfortunately, I’d run out of time (and money) and had to start working again. Work became all-consuming, and after spending 10-12 hours of skull sweat a day on technical matters, I didn’t have the energy or drive to devote to game programming when I got home. On the weekends, all I wanted to do was sleep.

I tried to pick it back up several times but couldn’t get back into the habit…

When Stars Align

That all changed this year. I have…

  • Started a new job with a pension, so now I have a future and retirement to look forward to.
  • Rid myself of $117,000 of student debt.
  • Nearly paid off my mortgage (8 months to go).
  • Lost 43 lbs. of excess weight through diet and exercise, and I am on track to be back to my ideal weight by the end of the year.

I’ve finally reached a point in my life where I can resume my pursuit of game development now that I have the time, energy, and resources to do so.

More to come…