Another fantastic video Robin! As always you make debugging entertaining and educating! 8BS&T is one of my favourite places on the Internet! Thanks for all you do!
At 2X size, the ship would weigh 8 times as much, but the engines would only produce 4 times the thrust. If it were a bug, the ship shouldn't be able to fly, so I think it's a feature.
This has nothing to do with the C64, but in 1983 I had a handheld Defender game with a 2-colour VFD and which ran off 4 C cells. That game was a ton of fun but it's long-gone now. Like everything from my childhood, I either wrecked it or lost it. Tragic. Great video Robin. This was a good time!
The Entex Defender game? I had that too! In fact, I still have it :) And I actually used it while making the end music; see if you recognize any of the sound effects.
The Entex Defender handheld got super popular again when it was featured in one of the Guardians of the Galaxy movies. I bought a beat-up one on eBay to fix and by the time I re-sold it it was worth more than I paid. I had one when I was a kid too, but it didn't really hold my attention so much all these years later.
I was not familiar with the brand name so I had to look it up, and that indeed looks like it (the flat version, not the one with the angled case). Taking it apart and destroying it is one of my greatest regrets. Games like that were such a blast. I wish i had saved mine, but I had no idea of the value of things or how technology and the times would change. Kids with their featureless touchscreens missed out on the experience of possessing discrete, tangible games and toys. Today everything is a mobile app which can and will turn to garbage or disappear eventually, if it's not garbage from day one. It's all ephemeral.
I didn't notice any corruption of the right side of the top radar bar in the larger (bug) view. Could that be a consequence of the reset fix ASM? Great video! I was a Defender pro on the original Atari game. Fun memories! New subscriber!
Great video! I suspect the programmer intended to set the vector to reset the VIC, exactly as you modified the code to do, and simply made a mistake in the address. Perhaps it wasn't yet common knowledge that the reset vector could be set in the first bytes of the cartridge header and that's why there is initialisation code to change it once the image has started running? The CLI, SEI sequence seems odd. Maybe they believe you had to toggle it on then off again to set it? Or perhaps there was a bug in early hardware that actually required that?
If memory serves, the Action Replay monitor's save command let you set the load address through an optional argument. I think I only ever used the feature a handful of times, but then it came in real handy.
That would be a handy feature. I added that to my list of possible future Super Snapshot enhancements as my friend Adrian Gonzalez has made an improved Snapshot ROM and I might be able to work with him on some ideas.
I'm sad that none of the ports to home consoles ever replicated the amazing explosions of the original arcade classic. I seem to recall that the game was shipped to arcades with the largest RAM memory ever used at the time of its release. When arcade games were using between 8k and 12k of RAM, Defender boasted a whopping 24k. I've got a few arcade emulation games but for some reason Williams Defender and Robotron ROM dumps are really hard to find. I always wished it was a bit easier though. I never got past the third or fourth round in the arcades. An expanded reboot or reimagining of the Defender world would be amazing.
For this and other reasons, one gets the impression that Atarisoft had a lot of pressure on them to get games out the door before some cataclysm befell them.
Warner Communications treated Atari as a cash cow and cared about deadlines much more than quality. The failure of ET and substandard Pacman were direct results of pressuring their programmers to meet deadlines instead of ensuring game quality. Warner also mistreated and underpaid Atari's programmers which we all know now was a massive error in judgment, resulting in programmers bailing out and starting both Activision and Imagic. These companies drained Atari of their best programmers and went on to directly compete against Atari's titles, often outdoing them. 50 years on, Warner still doesn't seem to have learned their lesson.
My favourite game of all time. Best port (for me) was for the BBC micro by Acornsoft. I got it when it was still called 'defender' not renamed to 'planetoid' due to copyright. I was so pleased to get this game home and play without loosing pocket money. It made economical sense for the out lay. Sadly the original and box and all have been lost (along with boxed Elite. Meh.).
i notice a small bug in your petreons credits at the end of your video. When the names can no longer indent further to the right and go back to the left the pause is half as short as the other lines. Did not see this bug in your coco video.
Very interesting Robin. I enjoyed playing Defender in the arcade as a kid but I don’t remember playing it on a C64 back then. Or least not much. I never had it but a buddy might have. Anyway I feel like Jumbo Jet mode needs to be a selectable option. 😀 With fixed up collisions and rear thruster again when going left. That looks fun. That’s one of those bugs where I think the programmer had to notice it when testing. Yet apparently they didn’t or just didn’t bother to fix it. Deadlines etc. The fact it is still playable makes it a neat Easter egg almost not just a bug.
Same for me, sorta.. I played it on the Atari (2600? had to be) many, many hours.. most likely thousands, and we would even have all-nighters where we would try to roll-over the score. I'll never forget somebody tripping over the cord around 2am and unplugging it.. We didn't care, we stayed up all night until we got it to roll over anyway. Fun times. If I had it on the C64, I don't remember it.
I seem to remember a much better version of Defender on the C64. It was best played using the keyboard. I'm really sure it wasn't this version, I'll have to do some research.
I really liked this one. And the game looks familiar I think. Maybe it's just that the little map at the top reminds me of Fort Apocalypse... as you know, my all time favourite C64 game. Have you done a video on Fort Apocalypse yet?
Thanks, yeah, Fort Apocalypse seems to have borrowed lots of different elements from games and ended up being a great game in its own right. I haven't covered Fort Apocalypse yet. Does it have any weird bugs or glitches or anything? I usually only get into a game if there's something unusual to figure out. :)
I remember in the late 70's playing Defender in an Arcade. The guy who maintained the place said this game would never be played at home because the resolution was too high.
It would be fun to rewrite the explosion code to use more sprites to make the explosion larger and more dramatic, like the arcade version, but the limited ROM space might be a problem. In that case, I believe there is a single-load version available.
I think that could still be done though, because the spaceship is on the screen by itself when it blows up. If necessary, they could even multiplex 8 sprites per horizontal area and make it look really good.
Hello Robin! Can you make a video about Micro adventure(books series with basic code in it)? But with a challenge:The SepTandy 2024 is started! So you can use only TRS computers
why not fix it so pressing restore toggles the register so that if youve got bad eyes you can have big sprites. instead of waiting for the explosion have a line of code in the boot sequence that just inverts whatevers already there??
Atari's great blunder - not taking up Archer McClean's conversion of defender. Good for him, he retooled it and made drop zone which is heaps better. No offence meant to the atarisoft author of the conversion meant.
Dropzone is the best shoot-em-up on the c64. I had Armalyte/Delta etc but they were just remembering patterns and got boring. Dropzone was pure reaction.
5:30 Crazy that the gameplay works so well in the glitchy mode 8:52 It's far more square-like on a PAL machine 16:52 Always nice when a file format is just a header, and the payload can be loaded via an offset. I did this recently with a SID file (just offset by $7e when loading) 18:45 Ah, "page $80", good trivia right there 24:22 A 2-bit fix this time :D (b3/b2) 28:39 I've had an easy flash cart for years, but I've not taken the time to figure out how to work it. Maybe in 2025...
Could you take a look at Crystal Castles and figure out why it crashes at level 9? I'm referring to the Thundervision version. I once tried to find an original copy to buy, but my searches came up empty. Maybe the original crashes in the same place...
Someone on X-Twitter also brought up Crystal Castles. Apparently that Thundervision version was unofficial, either a fan-made game or one that didn't get properly licensed and so it was leaked, so there isn't actually a retail version available at all. I watched a playthrough and it seems to crash at the very beginning of level 10, titled "The End". I put it on my list of things to potentially look into, thanks.
Aww, man, missed opportunities: You didn't show us what would happen if you hit Restore after the explosion in Jumbo Mode? Gargantuan Mode?? Nah, probably not. There was something else I wanted to mention, but I'm braindead at the moment and can't recall. One of my favorite games; thanks for showing us about this bug.
as always, great findings. Not familiar with this game at all. Hope you can find the time to make a video explaining how the loading works on The Last Ninja games, with that super cool effect where the screens are ensambled
Horrible video - for the past hour, my wife has been inspecting every single square centimeter of my body, mumbling "Where... Where... Where is his *RESTORE* key?!"...
2:31 You crashed into an alien ship, the game said "level complete", and then your ship exploded at the start of the next level. I suppose that "could" be viewed as completing the level. 22:37 Does it reset the stack pointer on an NMI? If not, you could overflow the stack by repeatedly pressing the RESTORE key. Though, the game might run fine with the stack wrapping around. 24:08 They could also have just made the NMI vector do nothing. Maybe they wanted a way to recover if their game crashed.
As soon as I saw the double-size sprites, I immediately thought "Fischer Price Defender!"
Another fantastic video Robin! As always you make debugging entertaining and educating! 8BS&T is one of my favourite places on the Internet! Thanks for all you do!
Great video Robin =D I wasn't aware of this bug in Defender! Quite cool to play it unfixed =D
I love the detective work that goes into finding the source of the problem.
At 2X size, the ship would weigh 8 times as much, but the engines would only produce 4 times the thrust. If it were a bug, the ship shouldn't be able to fly, so I think it's a feature.
Robin making the eighties even more perfect than they were..
The Speccy version of Defender, called Guardian II, is great. So is Ratsoft's Amiga game.
This has nothing to do with the C64, but in 1983 I had a handheld Defender game with a 2-colour VFD and which ran off 4 C cells. That game was a ton of fun but it's long-gone now. Like everything from my childhood, I either wrecked it or lost it. Tragic.
Great video Robin. This was a good time!
The Entex Defender game? I had that too! In fact, I still have it :) And I actually used it while making the end music; see if you recognize any of the sound effects.
The Entex Defender handheld got super popular again when it was featured in one of the Guardians of the Galaxy movies. I bought a beat-up one on eBay to fix and by the time I re-sold it it was worth more than I paid. I had one when I was a kid too, but it didn't really hold my attention so much all these years later.
I was not familiar with the brand name so I had to look it up, and that indeed looks like it (the flat version, not the one with the angled case). Taking it apart and destroying it is one of my greatest regrets. Games like that were such a blast. I wish i had saved mine, but I had no idea of the value of things or how technology and the times would change.
Kids with their featureless touchscreens missed out on the experience of possessing discrete, tangible games and toys. Today everything is a mobile app which can and will turn to garbage or disappear eventually, if it's not garbage from day one. It's all ephemeral.
I didn't notice any corruption of the right side of the top radar bar in the larger (bug) view. Could that be a consequence of the reset fix ASM? Great video! I was a Defender pro on the original Atari game. Fun memories! New subscriber!
Great video!
I suspect the programmer intended to set the vector to reset the VIC, exactly as you modified the code to do, and simply made a mistake in the address. Perhaps it wasn't yet common knowledge that the reset vector could be set in the first bytes of the cartridge header and that's why there is initialisation code to change it once the image has started running?
The CLI, SEI sequence seems odd. Maybe they believe you had to toggle it on then off again to set it? Or perhaps there was a bug in early hardware that actually required that?
If memory serves, the Action Replay monitor's save command let you set the load address through an optional argument. I think I only ever used the feature a handful of times, but then it came in real handy.
That would be a handy feature. I added that to my list of possible future Super Snapshot enhancements as my friend Adrian Gonzalez has made an improved Snapshot ROM and I might be able to work with him on some ideas.
I'm sad that none of the ports to home consoles ever replicated the amazing explosions of the original arcade classic. I seem to recall that the game was shipped to arcades with the largest RAM memory ever used at the time of its release. When arcade games were using between 8k and 12k of RAM, Defender boasted a whopping 24k.
I've got a few arcade emulation games but for some reason Williams Defender and Robotron ROM dumps are really hard to find.
I always wished it was a bit easier though. I never got past the third or fourth round in the arcades. An expanded reboot or reimagining of the Defender world would be amazing.
For this and other reasons, one gets the impression that Atarisoft had a lot of pressure on them to get games out the door before some cataclysm befell them.
Warner Communications treated Atari as a cash cow and cared about deadlines much more than quality. The failure of ET and substandard Pacman were direct results of pressuring their programmers to meet deadlines instead of ensuring game quality.
Warner also mistreated and underpaid Atari's programmers which we all know now was a massive error in judgment, resulting in programmers bailing out and starting both Activision and Imagic. These companies drained Atari of their best programmers and went on to directly compete against Atari's titles, often outdoing them.
50 years on, Warner still doesn't seem to have learned their lesson.
The sound when the game starts sounds suspiciously similar to the 8-Bit guy's older intro!
YES!! That is where I'd heard that sound! Good call. Thank you.
Thanks for answering my question!
Great video! You should make a custom crack screen that lets you enable/disable the bug.
My favourite game of all time. Best port (for me) was for the BBC micro by Acornsoft. I got it when it was still called 'defender' not renamed to 'planetoid' due to copyright. I was so pleased to get this game home and play without loosing pocket money. It made economical sense for the out lay. Sadly the original and box and all have been lost (along with boxed Elite. Meh.).
Agreed, Neil Raine's Planetoid which was released for the Beeb in '82, makes the Atarisoft C64 port look very pedestrian.
Man, that's a HUGE bug.
I think i discovered that CBM80 flag when doing a RUN/STOP+RESET to go into the monitor on my C128 with a C64 cartridge inserted.
They knew we would be old someday and have bad eyesight while still playing this,so they made the sprites expand so we could still see it 😆😆
i notice a small bug in your petreons credits at the end of your video. When the names can no longer indent further to the right and go back to the left the pause is half as short as the other lines. Did not see this bug in your coco video.
Very interesting Robin. I enjoyed playing Defender in the arcade as a kid but I don’t remember playing it on a C64 back then. Or least not much. I never had it but a buddy might have.
Anyway I feel like Jumbo Jet mode needs to be a selectable option. 😀 With fixed up collisions and rear thruster again when going left. That looks fun.
That’s one of those bugs where I think the programmer had to notice it when testing. Yet apparently they didn’t or just didn’t bother to fix it. Deadlines etc.
The fact it is still playable makes it a neat Easter egg almost not just a bug.
Same for me, sorta.. I played it on the Atari (2600? had to be) many, many hours.. most likely thousands, and we would even have all-nighters where we would try to roll-over the score. I'll never forget somebody tripping over the cord around 2am and unplugging it.. We didn't care, we stayed up all night until we got it to roll over anyway. Fun times. If I had it on the C64, I don't remember it.
I seem to remember a much better version of Defender on the C64. It was best played using the keyboard. I'm really sure it wasn't this version, I'll have to do some research.
It was called Guardian
Dropzone? I had that on the 800XLand it was awesome
I really liked this one. And the game looks familiar I think. Maybe it's just that the little map at the top reminds me of Fort Apocalypse... as you know, my all time favourite C64 game. Have you done a video on Fort Apocalypse yet?
Thanks, yeah, Fort Apocalypse seems to have borrowed lots of different elements from games and ended up being a great game in its own right. I haven't covered Fort Apocalypse yet. Does it have any weird bugs or glitches or anything? I usually only get into a game if there's something unusual to figure out. :)
Looks like an instant Vic20 port.
I remember in the late 70's playing Defender in an Arcade. The guy who maintained the place said this game would never be played at home because the resolution was too high.
funny, it released to arcades in 1981.
@jasonm07 oops, early 1980's then.
It would be fun to rewrite the explosion code to use more sprites to make the explosion larger and more dramatic, like the arcade version, but the limited ROM space might be a problem. In that case, I believe there is a single-load version available.
I think that could still be done though, because the spaceship is on the screen by itself when it blows up. If necessary, they could even multiplex 8 sprites per horizontal area and make it look really good.
@@JustWasted3HoursHereCartridges were usually 8k or 16k. A 100% version probably wouldn't fit in a cartridge
@@phill6859 Every time I think something can't be done on the C64 some clever programmer proves me wrong, so you never know!
Hello Robin! Can you make a video about Micro adventure(books series with basic code in it)? But with a challenge:The SepTandy 2024 is started! So you can use only TRS computers
why not fix it so pressing restore toggles the register so that if youve got bad eyes you can have big sprites. instead of waiting for the explosion have a line of code in the boot sequence that just inverts whatevers already there??
Atari's great blunder - not taking up Archer McClean's conversion of defender. Good for him, he retooled it and made drop zone which is heaps better. No offence meant to the atarisoft author of the conversion meant.
Dropzone is the best shoot-em-up on the c64. I had Armalyte/Delta etc but they were just remembering patterns and got boring. Dropzone was pure reaction.
5:30 Crazy that the gameplay works so well in the glitchy mode
8:52 It's far more square-like on a PAL machine
16:52 Always nice when a file format is just a header, and the payload can be loaded via an offset. I did this recently with a SID file (just offset by $7e when loading)
18:45 Ah, "page $80", good trivia right there
24:22 A 2-bit fix this time :D (b3/b2)
28:39 I've had an easy flash cart for years, but I've not taken the time to figure out how to work it. Maybe in 2025...
Could you take a look at Crystal Castles and figure out why it crashes at level 9? I'm referring to the Thundervision version.
I once tried to find an original copy to buy, but my searches came up empty. Maybe the original crashes in the same place...
Someone on X-Twitter also brought up Crystal Castles. Apparently that Thundervision version was unofficial, either a fan-made game or one that didn't get properly licensed and so it was leaked, so there isn't actually a retail version available at all. I watched a playthrough and it seems to crash at the very beginning of level 10, titled "The End". I put it on my list of things to potentially look into, thanks.
Aww, man, missed opportunities: You didn't show us what would happen if you hit Restore after the explosion in Jumbo Mode? Gargantuan Mode?? Nah, probably not. There was something else I wanted to mention, but I'm braindead at the moment and can't recall. One of my favorite games; thanks for showing us about this bug.
I got this game with my C64 in 1985 at age 16. I played this game night and day until the score counter broke and started showing odd characters
as always, great findings. Not familiar with this game at all. Hope you can find the time to make a video explaining how the loading works on The Last Ninja games, with that super cool effect where the screens are ensambled
Somehow the expanded more looks better.
Only canadians would take out a feature like that.
Is it intended or a nitendo ?
Nintendon't!
Okay, but the lasers aren’t larger.
I think that implies the lasers are characters and not sprites.
Definitely need an "always jumbo" fix. :-)
That’s… what she said.
Please fix Sea Fox
What's wrong with Sea Fox? Is it the C64 version?
Horrible video - for the past hour, my wife has been inspecting every single square centimeter of my body, mumbling "Where... Where... Where is his *RESTORE* key?!"...
2:31 You crashed into an alien ship, the game said "level complete", and then your ship exploded at the start of the next level. I suppose that "could" be viewed as completing the level.
22:37 Does it reset the stack pointer on an NMI? If not, you could overflow the stack by repeatedly pressing the RESTORE key. Though, the game might run fine with the stack wrapping around.
24:08 They could also have just made the NMI vector do nothing. Maybe they wanted a way to recover if their game crashed.
I'm going to choose to call it an oblong, just to be pedantic. 🤣
Notification Squad! :)
13891. 38911.. spooky.