Purgatory (Limbo Themed Pitfall Hack)

[LatchKeyKid]

Hey folks!  I'm new to the 2600 scene and decided to dip my toes into the homebrew pool over on the shallower hacking end due to having almost zero programming knowledge or experience.  I decided to go with a Pitfall hack themed after a much more recent indy game, Limbo.  It's still Pitfall in gameplay but I've changed the graphics (sprites and colors) and a bit of the sound to the more muted style of Limbo.  Thanks to all those who have helped over the past couple weeks as I've been trying put this out including @Thomas Jentzsch for the original disassembly, @alfredtdk for his tips on sprite and color swaps, @Nukey Shay for the code to animate previously static objects, and @alex_79 and @orange808 for help with B&W and sound coding!

 

 

I still hope to in the future add a short tune (8 notes that I've got the TIA codes for) to the intro and death tunes but that will take a bit more time (and learning!) on my part to accomplish.  There is a glitch in that when you die due to the newly animated centipede while on the ladder that you respawn on an invisible clipped ladder instead of dropping down from the tree tops.  You're not stuck but can move up and down the invisible ladder to get off and/or avoid the cycling insect though.  For those with PAL displays, let me know if the B&W palette still works as in the NTSC screenshot below.  I set Stella to PAL but it gave me a very dark screen regardless of what colors I set in the code so I'm not sure if that's just a display problem on my end (NTSC laptop screen?) or if it's actually happening on PAL displays as well.

 

Edit:  I've finally added the v1.4 version to this first post as I didn't catch that it wasn't posted here for ease of download.  It should be the final one for the forseeable future unless someone finds a major game breaking bug introduced as a result of my hack!

Purgatory V1.0.bin

Purgatory v1.4.bin

Edited November 25, 2023 by LatchKeyKid

[alfredtdk]

My congratulations, your hack turned out very, very good. It really reminds me of the Limbo game. Looks like you finally got around the black color problem with the wells. Very good.
Do you want to add music or sound effects? If I remember correctly, the game Limbo almost or does not have a soundtrack, leaving only the disturbing sound of objects or creatures hidden in the darkness. I would prefer some sound effects like night birds or creaking doors. Who knows also the sound of footsteps.
I think with the help of the community this Pitfall hack could become one of the best hacks ever made.
Purgatory with soundtrack and a few more sound effects would be great.

[LatchKeyKid]

Thanks!  That's very high praise and likely undeserved in my case but I appreciate it.  I initially started work on the first version of the hack back in April but had to take a month break due to personal reasons and it morphed into a Limbo inspired version of Pitfall when I came back to it.  I do want to add limited sound to it; footsteps are on the to do list as well as a short intro/end of game tune but I don't think I could add any more than that and still fit in the 4k limit without cutting other things out.  And that's before considering my own (lack of) programming knowledge as I'm basically looking/asking for advice and then brute force trial and error'ing it until it works.

[alfredtdk]

If the reason for 4k is the cause of preventing additions, you might be doing database switching, imagine what you could do with more 28k available. 

Take the example of Venture Reloaded, by  @Thomas Jentzsch , and  compare it to the original Venture of the time. A simple 4k game, based on Arcade, and expanded to a 32k ROM.
The difference you already notice in the title screen, absent in the original 2600. The music and sound effects added are perfect.

 

[TrekMD]

That looks great!

[LatchKeyKid]

5 hours ago, alfredtdk said:

If the reason for 4k is the cause of preventing additions, you might be doing database switching, imagine what you could do with more 28k available. 

Take the example of Venture Reloaded, by  @Thomas Jentzsch , and  compare it to the original Venture of the time. A simple 4k game, based on Arcade, and expanded to a 32k ROM.
The difference you already notice in the title screen, absent in the original 2600. The music and sound effects added are perfect.

 

I appreciate the vote of confidence but that is way beyond me!  I'm struggling right now with how to add a simple sound with a particular walking animation sprite without causing an error that won't compile.  While I haven't actually done the count, I wonder if adding the two lines puts me over the scan line CPU cycle limit already.  The disassembly is a big help trying to make sense of what is going on.  if I were to start a new game though, I'd definitely go with bB and 32k as the max size.  When i'm done with this one, i'll probably try another hack first though (one with easy to plug in music this time!).

 

3 hours ago, TrekMD said:

That looks great!

Thanks!  I hope to improve on it a bit in the future if things work out.

[glurk]

I like this, B/W as a thematic element really suits the 2600, and I'm not sure it's really been done before.  It changes the whole mood.  I took the 'liberty' of changing the number font a bit, it makes it look better to me in some way...  Apologies for messing with your hack...  ?

 

Purgatory V1.0f.bin

[LatchKeyKid]

Thanks and feel free!  I hadn't considered changing the font but it's a good idea and I might incorporate my own font tweaks for the next version in addition to hopefully some audio tweaks.

[Bomberman94]

Here are pictures captured on a real CRT with original Atari 2600 (light 6er) PAL system. For me brightness is fine (in real it is a bit lighter than on the pictures). I really like the B/W style and new graphics ?

Edited June 16, 2022 by Bomberman94

[LatchKeyKid]

Thanks both for the compliment and for checking it on PAL!  I'm glad it works.  On Stella when I set the display to PAL, this is the darkness that I was getting.  I didn't change the refresh rate to 50hz (not sure how on my laptop or even if I can) so maybe that's contributing to it.

 

 

[Thomas Jentzsch]

On 6/13/2022 at 10:39 PM, alfredtdk said:

Take the example of Venture Reloaded, by  @Thomas Jentzsch...

That's not from me, but from @Omegamatrix.

[+ZeroPage Homebrew]

On 6/14/2022 at 11:42 PM, glurk said:

I like this, B/W as a thematic element really suits the 2600, and I'm not sure it's really been done before.

The B&W aesthetic and artwork is really great in this hack. There's been a couple of excellent looking B&W homebrews for the 2600 that come to mind:

• Spies in the Night
• Shattered Earth

- James

 

 

[LatchKeyKid]

13 hours ago, ZeroPage Homebrew said:

The B&W aesthetic and artwork is really great in this hack. There's been a couple of excellent looking B&W homebrews for the 2600 that come to mind:

• Spies in the Night
• Shattered Earth

- James

 

 

Thanks!  I wasn't aware of prior B&W games whether official or homebrew for the Atari 2600 being new to the scene (other than the obvious joke that many "gaming" tv's for kids in the 80's including mine made every game B&W by default!).   I did discover one on your own youtube channel that was incredibly atmospheric and really does justice to the asthetic called Plague.  Nothing I could create could come close to this but I do hope to at least add footsteps but that programming is currently eluding my meager abilities which are currently stumped just adding footsteps.

 

 

[Arenafoot]

On 6/18/2022 at 6:32 PM, ZeroPage Homebrew said:

The B&W aesthetic and artwork is really great in this hack. There's been a couple of excellent looking B&W homebrews for the 2600 that come to mind:

• Spies in the Night
• Shattered Earth

- James

 

 

and also:

Spies in the Night 2 (coming soon)

https://atariage.com/forums/topic/283621-complete-spies-in-the-night-2

 

 

[LatchKeyKid]

Sorry it took so long but I finally updated the hack with a few minor tweaks like to the sound effects and sprites.  I also changed the insect sprites size, placement, and numbers for added difficulty as well.  I wasn't able to add an intro/outro tune as I had hoped (though I did get the notes that I wanted programmed) due to the very tight space limitations in the ROM.  I only had 9 total lines of code to work with after pruning unnecessary bits (and even the constantly scrolling copyright!) but I was able to add footsteps that are supposed to resemble a heartbeat.  Let me know if the constant pitter patter is annoying as I acknowledge that might be the case after a while.  Barring any major epiphanies regarding adding the music, I expect this update to be the final release.  I hope you all enjoy and appreciate any feedback on the changes.

 

 

 

 

Purgatory V1.1.bin

[alfredtdk]

I liked the sound of the heartbeat, it gives a more distressing atmosphere to the game.
I found a bug right at the beginning of the game, after going through the spider/scorpion in the underground. When you are hit by the insect while standing still on the stairs, it resurrects a little further on, below the ground, leaving its head visible, and it is possible to get out or go down a little more, which causes the loss of all lives if you go down completely. The attached video shows more detail of the bug. I haven't tested if in other parts of the game this happens.

[LatchKeyKid]

Thanks.  Unfortunately it's a known bug (pun intended) that I haven't been able to fix.  I mentioned it in the first post but it's good to repeat it here.  You're caught in the middle between kernels and respawn on an imaginary ladder there that you can jump out of by pressing left or right.  You pointing it out will hopefully spur me to find out why it happens at that point but it may be beyond my programming/debugging abilities honestly.

 

Edited August 5, 2022 by LatchKeyKid

[LatchKeyKid]

I fixed it!  I guess I just needed the motivation of you reminding me and not having to focus on trying to add the sounds instead.  I had to remove two more lines to add in the fix so hopefully I didn't add in any bugs.  The only change should be that Harry faces the same direction when he respawns as when he died instead of always facing to the right after a respawn.   Let me know if that fix works for me (and if there are any other unforseen issues!).

Purgatory v1.2.bin

[Bomberman94]

On 8/5/2022 at 3:57 AM, LatchKeyKid said:

I fixed it!  I guess I just needed the motivation of you reminding me and not having to focus on trying to add the sounds instead.  I had to remove two more lines to add in the fix so hopefully I didn't add in any bugs.  The only change should be that Harry faces the same direction when he respawns as when he died instead of always facing to the right after a respawn.   Let me know if that fix works for me (and if there are any other unforseen issues!).

Purgatory v1.2.bin 4 kB · 7 downloads

- footstep noise: fine and not disturbing because low noise

- changes in difficulty: great idea

- if man respawns the enemy objects remain on screen and man could fall directly into enemy and dies again. Better to „reset“ location of enemies, too. 
- you have changed the design of score/timer but in the meantime changed it back to „original“. I liked the new look more - if the others agree please bring it back - this was the other/new design and what I’m thinking about:

 

[LatchKeyKid]

Thanks and good to hear that the footsteps don't get too monotonous (especially on read hardware!).   Regarding the font, it was actually Glurk who modified it for himself and posted it above.  Now that I've gotten the major bug out of the way (ladder) and the footsteps in, I might take a look at the font myself as well. 

 

I also encountered that problem where you fall into an enemy following the one that kills you.  I like your idea of resetting their placement and will see if I can do that (and what lines of code I can cut to do so as even putting in a single line of code causes the compiler to fail with the original 4k size I want to keep).   When I doubled the wasps (I'm guessing that's what killed you), you can fall into the second one if you get killed by the first on the left edge of the screen.  I suppose it could also happen if you got killed by the centipede closer to the middle as well due to it's wider size.  Animating the previously static hazards (fire and cobra) caused these unexpected issues and it's obviously compounded when I change them further by doubling/widening them.  I had to change their original placement as well through trial and error as if you're speedrunning you could literally run into them when transitioning onto a new screen or have them run into you if you don't immediately move.

[Bomberman94]

14 minutes ago, LatchKeyKid said:

Thanks and good to hear that the footsteps don't get too monotonous (especially on read hardware!).   Regarding the font, it was actually Glurk who modified it for himself and posted it above.  Now that I've gotten the major bug out of the way (ladder) and the footsteps in, I might take a look at the font myself as well. 

 

I also encountered that problem where you fall into an enemy following the one that kills you.  I like your idea of resetting their placement and will see if I can do that (and what lines of code I can cut to do so as even putting in a single line of code causes the compiler to fail with the original 4k size I want to keep).   When I doubled the wasps (I'm guessing that's what killed you), you can fall into the second one if you get killed by the first on the left edge of the screen.  I suppose it could also happen if you got killed by the centipede closer to the middle as well due to it's wider size.  Animating the previously static hazards (fire and cobra) caused these unexpected issues and it's obviously compounded when I change them further by doubling/widening them.  I had to change their original placement as well through trial and error as if you're speedrunning you could literally run into them when transitioning onto a new screen or have them run into you if you don't immediately move.

Killed after respawn: situation was running to left (right from the start), dying at the right side but man appeared left (like you run to the right). At this point there was an enemy left and I touched it then. 

[LatchKeyKid]

Thanks.  I'll try to replicate that.  One downside to animating the static enemies is that if you go left they still respawn to the right and you have to move (or keep moving) to prevent being killed.  Initially, you'd die instantly if you didn't keep moving but I've changed the location of the spawns so that you have a second to start and won't instantly run into enemies either (also a thing initially).  Changing the spawn side depending on the location (whether going left or right) is beyond my current abilities but regardless would require me removing a big chunk of other code in order to get it done under the original 4k size limitation.   

[LatchKeyKid]

On 8/6/2022 at 9:06 AM, Bomberman94 said:

Killed after respawn: situation was running to left (right from the start), dying at the right side but man appeared left (like you run to the right). At this point there was an enemy left and I touched it then. 

Well, I think I've fixed the falling into the enemy when respawning glitch without messing up the fish or treasures.     I had to remove some code as I have zero lines to spare to fit in 4k but hopefully it won't be too noticeable.  I tweaked up the volume a bit on the footsteps since they weren't as annoying as I feared.  If and when you get a chance, let me know if the display still works well as I had to change some wsync code lines; it still works fine in the stella emulator but real hardware can make a difference.  I've decided to keep the same text font for the counters as a callback to the original Pitfall game I started with.

 

Assuming I didn't introduce any new bugs with my "fix", this should be the last version of the hack.  I wanted to add Limbo-style asthetics to the game as well as increase the difficulty (beyond just rushing for time) and I think I've given the classic a bit more to worry about for players.    Thanks again to all who took a look at it and posted feedback as well as those who helped with coding advice!

Purgatory v1.3.bin

[Bomberman94]

2 hours ago, LatchKeyKid said:

Well, I think I've fixed the falling into the enemy when respawning glitch without messing up the fish or treasures.     I had to remove some code as I have zero lines to spare to fit in 4k but hopefully it won't be too noticeable.  I tweaked up the volume a bit on the footsteps since they weren't as annoying as I feared.  If and when you get a chance, let me know if the display still works well as I had to change some wsync code lines; it still works fine in the stella emulator but real hardware can make a difference.  I've decided to keep the same text font for the counters as a callback to the original Pitfall game I started with.

 

Assuming I didn't introduce any new bugs with my "fix", this should be the last version of the hack.  I wanted to add Limbo-style asthetics to the game as well as increase the difficulty (beyond just rushing for time) and I think I've given the classic a bit more to worry about for players.    Thanks again to all who took a look at it and posted feedback as well as those who helped with coding advice!

Purgatory v1.3.bin 4 kB · 4 downloads

… just a question: does it matter if your use a PAL or NTSC console because it is B/W?

[LatchKeyKid]

I don't know if it does.  I assumed from your location that you were using PAL and was/am very grateful for you checking it out on read hardware/tv.  I didn't change any of the colors or timing with this iteration but rather just took out some WSYNCs before the VSYNC.   All the graphics seem to still be loading up on my NTSC Stella laptop normally and on the same scanlines.