Intellivision Game Glitches

[cparsley]

I wanted to post this to the men and women with the best knowledge of the INTV, the STIC and all the components and programming needed for a software title to run effectively on the Intellivision.

 

On some titles, namely Demon Attack, Atlantis, Frogger to name a few, have a game fatal glitch that "randomly" goes off without knowledge ahead of time, causing the game to automatically be over. I say "randomly" as we do not know 100% why the glitch occurs. 

 

This is why I'm posting the question here.... Can anyone with a programmers mind look at Demon Attack, Frogger etc and find out what and why the glitch occurs specifically? Thanks in advance for your time reading this, and for looking into it for the good of all Intellivision users worldwide.

[cparsley]

For some who may ask, what glitches, let me point out a few in the games listed above, and when it may occur from a layman's (players) perspective (not a programmers)

 

Demon Attack - Imagic

 

There are actually two glitches here, one is way way more pronounced than the other. The major one is where the game during play will immediately crash, have the enemies fly in a straight line rather than the game patterns, and all collision detection is gone. Game terminates as can't not progress from this point. The only known position that this glitch seems to have a chance of going off is when the player has the maximum six lives in reserve. (there are also examples in this season's HSC of the game, if needed)

 

The not as often glitch occurs during the mother ship battle at the point of destroying the mothership (and the shaking explosions). The shaking either doesn't end (Game terminates) or the shaking does terminate, but the game will not proceed to the portion of code to return to the surface for the next wave to begin. (Also game terminates) There doesn't seem to be a layman's idea as to when this glitch would occur, but happens less often than the before listed glitch.

 

 

Frogger - Parker Brothers

 

There is a serious game ending glitch in Frogger, that surprisingly calls to the Intellivision's cheering sound effect bank, with the problem with it never returning (Game Terminates). There does not seem to be any definite reason why this occurs, but the further the game goes, more likely the glitch to occur at any time. Can happen at any part, road, middle, river, etc... (there are several examples in the this week Intellivision HSC ending tonight for examples if needed)

 

 

Atlantis - Imagic

 

This one isn't per say as much a glitch, but a forced game over situation. On day 12, I believe it will crash and hang, not allowing any more destruction of any enemies nor destruction of the Atlantis town. No way to get around this, regardless of level (Easy, Medium, Hard)

 

Thanks again in advance.

[mr_me]

Bugs can be hard to figure out; more so without commented source code.  Here's what the Demon Attack programmer had to say about it.

 

"Yes, I knew about it. I never found the cause for it. It really ruined the joy of seeing people buying the game in stores. It still bothers me to this day. I suspect it has something to do with interrupts. I saw it mostly happen after lifting off to go to the Demon Base. The Base would never show up and you would drift until you hit the reset button."

 

http://www.classic-consoles-center.at/interviews/interview-with-gary-kato

Edited May 25, 2021 by mr_me

[Tempest]

I always found the Atlantis one interesting.   I thought someone had figured out what triggered it during one of the high score contests, but I might be mistaken.

 

A lot of these bugs come from people mastering the game and playing it longer than 99.9% of the population would.  I think that's why many of them weren't seen until years later when online high score contests and emulation became a thing.

[Mik's Arcade]

12 hours ago, mr_me said:

Bugs can be hard to figure out; more so without commented source code.  Here's what the Demon Attack programmer had to say about it.

 

"Yes, I knew about it. I never found the cause for it. It really ruined the joy of seeing people buying the game in stores. It still bothers me to this day. I suspect it has something to do with interrupts. I saw it mostly happen after lifting off to go to the Demon Base. The Base would never show up and you would drift until you hit the reset button."

 

http://www.classic-consoles-center.at/interviews/interview-with-gary-kato

 

I know it bothers him, and I don't blame, but he can be rest assured that gamers love Demon Attack and can live with this glitch.

[+cmadruga]

I think someone with the knowledge could in principle debug the roms and try to answer the original question.

@Zendocon comes to mind, but I'm sure he's got a full plate already.

 

Either way, just knowing why the bugs happen doesn't do much. At best it could lead to work arounds.

The real deal would be to have the bugs somehow fixed. That is much more complicated, of course.

 

Maybe if we were talking about doing "super pro" releases, there could be some energy around fixing the issues.

[Zendocon]

1 hour ago, cmadruga said:

I think someone with the knowledge could in principle debug the roms and try to answer the original question.

@Zendocon comes to mind, but I'm sure he's got a full plate already.

Demon Attack isn't one I've gotten around to hacking just yet.  I've been working on something else lately.

 

I took a crack at Backgammon recently by request, and then let someone else take over and finish the job.