ColecoVision Games with Unused Code?

[ColecoFan1981]

Were there any ColecoVision games that had any unused code? This includes but is not limited to things such as extra characters and extra music.

 

Sometimes, intended code may go unused due to errors in coding. Coding errors are also why some games like Donkey Kong have bugs that affect graphics and/or gameplay.

 

I know that Victory for the PAL market was programmed differently in that the "unused" code present in the NTSC release was properly coded, and I would like to fix the NTSC release to do so.

 

~Ben

Edited April 4 by ColecoFan1981

[+Psionic]

Sector Alpha by Spectravideo has a programming bug similar to the one in Victory.  TCRF has a list of ColecoVision games with extra code but most of them are just hidden credits or other text.

[+evg2000]

Have you checked to see if there is a fixed version already?  there is a sce version someone did years ago.

[Ikrananka]

4 hours ago, Psionic said:

Sector Alpha by Spectravideo has a programming bug similar to the one in Victory.  TCRF has a list of ColecoVision games with extra code but most of them are just hidden credits or other text.

Just to clarify, Sector Alpha's issue was a cartridge hardware error and not a programming error.  The issue with the North American release of Victory was a corruption of the final ROM (2 bytes) prior to manufacturing the carts.

[Ikrananka]

16 hours ago, ColecoFan1981 said:

I know that Victory for the PAL market was programmed differently in that the "unused" code present in the NTSC release was properly coded, and I would like to fix the NTSC release to do so.

Victory for the PAL market matches exactly what the game designer, Paul Jaquays, signed off as final for the original North American release.  However, the ROM was corrupted (2 bytes) before it went to manufacturing.  When Victory was manufactured and released in PAL markets the original uncorrupted ROM was used.  These 2 bytes are the only difference between the NTSC and PAL releases.

 

Remember that all 1982 to 1985 ColecoVision releases used the same code for both NTSC and PAL markets.  There was no regionalisation in the code for ColecoVision games.  In fact this is the same for all of the ColecoVision homebrew games with a few exceptions.

 

Please refer to my CV ROM Update project notes for further info.

[NIAD]

13 hours ago, Psionic said:

TCRF has a list of ColecoVision games with extra code but most of them are just hidden credits or other text.

Thanks for the link.

 

As far as Easter Eggs go, I think War Room takes the cake !!!

 

[ColecoFan1981]

15 hours ago, Ikrananka said:

Victory for the PAL market matches exactly what the game designer, Paul Jaquays, signed off as final for the original North American release.  However, the ROM was corrupted (2 bytes) before it went to manufacturing.  When Victory was manufactured and released in PAL markets the original uncorrupted ROM was used.  These 2 bytes are the only difference between the NTSC and PAL releases.

 

Remember that all 1982 to 1985 ColecoVision releases used the same code for both NTSC and PAL markets.  There was no regionalisation in the code for ColecoVision games.  In fact this is the same for all of the ColecoVision homebrew games with a few exceptions.

 

Please refer to my CV ROM Update project notes for further info.

That makes me curious, that Coleco (unlike Nintendo) did not bother making tweaks to the basic NTSC coding to make gameplay faster against the slower 50 Hz refresh rate. Even Atari's 2600, 8-bit computer and 5200 titles did not have any region-specific coding changes from NTSC's 60 Hz. I believe no changes to the NTSC coding were done here in the pre-crash era since the developers would have had to use fractional rates (and sometimes non-integer-based replacement values) to adjust for 50 Hz, and might have made such region-specific versions cost more due to the extended coding work.

 

Also, the graphics chips in the consoles themselves may be different between NTSC and PAL (i.e. our NTSC ColecoVision uses the TI TMS9928A, but for PAL it's the slightly different TMS9929A) and so colors may show differently in PAL than in NTSC.

 

In fact, the only exception to the rule was that some PAL CBS ColecoVisions actually have a short 3-second (!) delay before the skill level select screen appears.

 

~Ben

Edited April 5 by ColecoFan1981

[else]

Quote

Even Atari's 2600, 8-bit computer and 5200 titles did not have any region-specific coding changes from NTSC's 60 Hz.

Maybe I'm not understanding what's being said here, but I thought Atari 2600 games famously had to be re-coded for pal.  Also, since a pal 5200 system never existed, it's not possible to say that 5200 games were or weren't region specific -- none of it exists....

Edited April 7 by else

[opcode]

On 4/5/2024 at 6:56 AM, ColecoFan1981 said:

That makes me curious, that Coleco (unlike Nintendo) did not bother making tweaks to the basic NTSC coding to make gameplay faster against the slower 50 Hz refresh rate. Even Atari's 2600, 8-bit computer and 5200 titles did not have any region-specific coding changes from NTSC's 60 Hz. I believe no changes to the NTSC coding were done here in the pre-crash era since the developers would have had to use fractional rates (and sometimes non-integer-based replacement values) to adjust for 50 Hz, and might have made such region-specific versions cost more due to the extended coding work.

 

Also, the graphics chips in the consoles themselves may be different between NTSC and PAL (i.e. our NTSC ColecoVision uses the TI TMS9928A, but for PAL it's the slightly different TMS9929A) and so colors may show differently in PAL than in NTSC.

 

In fact, the only exception to the rule was that some PAL CBS ColecoVisions actually have a short 3-second (!) delay before the skill level select screen appears.

 

~Ben

Adjusting from 60Hz to 50Hz isn't trivial in most cases (I mean, in terms of ColecoVision). Music playback is fairly easy to adjust, but movement of all the screen elements might be a big headache. I feel sorry for all PAL CV users out there, as they keep playing everything 20% slower than it should be.