I have been learning Godot and I have managed to successfully recreate Sonic's physics from the Genesis games while using the actual engine functionality. Would anyone be interested in a video series about recreating Sonic 1 or something in Godot with this stuff?
To trigger Knuckles' obscure "shooing" animation in Sky Sanctuary, Sonic's center position must be within the highlighted area, he must be facing left towards Knuckles, and he must be ducking.
If your Backup RAM (used for storing save data) data is corrupted, in English, it will display this error message, implying that "Robotonic" messed with it.
I have been learning Godot and I have managed to successfully recreate Sonic's physics from the Genesis games while using the actual engine functionality. Would anyone be interested in a video series about recreating Sonic 1 or something in Godot with this stuff?
There are some sprites that can be found in the 1996 PC version, but NOT the Sega CD version. These rolling sprites do exist in the v0.02 prototype, albeit unused. The shrinking sprites only exist via leftover mappings data in Tidal Tempest since 510; no tile data can be found.
Issue 20 of the French gaming magazine Mega Force features a build of Sonic CD between the v0.51 and 712 prototypes that interestingly has a signpost sprite that isn't seen in any of the dumped prototypes.
In Sonic 1, the lives counter icon in the HUD and the 1UP icon in the monitors use separate graphics. Interestingly, there's a 2 pixel difference between the two.
So, a developer for the PC port of Sonic CD (Dino version) had joined Retro and mentioned they had an archive of a *late beta* for the PC port (v0.992). I reached out to them and have been given permission to share it for preservation!
The following thread is a repost of a post by Clownacy on Sonic Retro: the ring sound bug.
In the other games, every time the player collects a ring, the ring sound plays on a different speaker, alternating between left and right, which is why is sounds as smooth as it does.
Ever wanted to know why Green Hill Zone in the Nick Arcade prototype is so broken? Well, when we take a peek at the collision map... oh dear.
[Technical explanation in replies]
This account is full of them. But, here's a new one:
The title screen is programmed to run at 30 FPS, but due to the process of rendering the clouds, copying them to VRAM, and also updating the everything else at once, it drops to 20.
Here's what it looks like at 30 FPS.
There are instances where Sonic's palette uses a more saturated blue compared to his in-game palette. This particular palette comes from a potential prototype palette from Sonic 1's development found in some digitizer files.
Issue 20 of the French gaming magazine Mega Force features a build of Sonic CD between the v0.51 and 712 prototypes that interestingly has a signpost sprite that isn't seen in any of the dumped prototypes.
If you have an astute eye, you can see that the drowning countdown numbers are actually bubbles that come out of Sonic's mouth. (Yes this is in all the Genesis titles, but it's also in CD, so...)
Also, the colors are a bit messed up here in Sonic CD for when the number forms.
In Green Hill Zone Act 1, with a well timed jump on the loop, you can go into the S-tunnel really quickly, and end up outrunning the bottom boundary of the stage that's gradually shifting downwards upon entering the area. On the bottom is an expanded view to show that boundary.
Looks like a lot of you want to see this come to fruition. Well, fear not, as I shall deliver... eventually. With me also having a job and other real life stuff, it may take a while. But, once the videos start coming out, I hope you will enjoy them!
I have been learning Godot and I have managed to successfully recreate Sonic's physics from the Genesis games while using the actual engine functionality. Would anyone be interested in a video series about recreating Sonic 1 or something in Godot with this stuff?
If anyone is interested, a while ago, LuigiXHero and I made a hack of Sonic 1 for the Sega Genesis that brings in the changes made in Sonic Jam. (Link below)
Sonic 2's camera is known for lagging behind Sonic when he's moving too quickly. The reason that happens is due to the stage renderer only being able to draw directly where the camera is at, regardless of how far it has moved. Areas that should have been drawn to get skipped.
It seems there is some misinformation regarding how to access this screen on only the Sega CD version of Sonic CD. Probably a mix-up with how to access it on the 1996 PC version.
You can only access it from Visual Mode. Technical breakdown in the replies.
The way Chaotix handles changing the speed of music for things like speed shoes involves changing the rate in which sound is updated
Twice every frame, it uses self modifying code to increment a counter by a certain amount, and if that counter overflows, a sound update is called
Hidden Palace Zone in Sonic 2 seems to have been developed so early on that it retains data that is more compatible with Sonic 1 than Sonic 2.
**This is just speculation**, but the monitor types look to be set before the IDs were updated, and thus still use the Sonic 1 IDs.
Green Hill Zone Act 2's "Normal" layout in Sonic Jam modifies the section with the pits and large platforms to block off the pits. They added barriers, spikes, and platforms, the last 2 which have new subtypes to extend their hitboxes, so that Sonic can't fall through any cracks.
The original 1993 version of Sonic CD has a hidden tag object for propelling Sonic into a ball (typically used for tunnels) placed right on a spring in Stardust Speedway Act 2. This tag object is missing in the 2011 remake.
There is an unreferenced bridge object in the v0.02 prototype that was originally assigned to ID 0x25. By adding it back to the object list, you can see that they were actually placed in the level, and were just hidden via being removed from the object list.
In the remake of Sonic 3 & Knuckles, finishing an act shows a score tally which gets your total score for the level.
What's interesting is that a part of it is actually using code that's unchanged from Sonic Mania!
[Explanation in replies]
Worth noting is that Sonic Jam fixes this by directly setting the bottom boundary value instead of making it gradually shift down. Here's that fix applied to a regular Sonic 1 ROM + expanded view.
In Green Hill Zone Act 1, with a well timed jump on the loop, you can go into the S-tunnel really quickly, and end up outrunning the bottom boundary of the stage that's gradually shifting downwards upon entering the area. On the bottom is an expanded view to show that boundary.
The 1207 prototype of Knuckles Chaotix has a super early time attack menu that can only be accessed in a peculiar way. You must do 2 full rotations of the player selection screen, select your character, your NPC partner character, and then you'll get access to it.
There is an unused animation of Sonic sneezing, which is well documented already. Did you know that there was actually some code that was implemented for it that never got used?
Hidden Palace Zone in Sonic 2 seems to have been developed so early on that it retains data that is more compatible with Sonic 1 than Sonic 2.
The 2nd palette line closely resembles Sonic 1's Green Hill Zone's, just modified to be able to display Sonic 2's ring sprite properly.
In the remake of Sonic 3 & Knuckles, when you interact with the bonus stage warp from a Starpost, the game fades to white with a warp sound effect.
This is actually not accurate to the original game.
In the remake of Sonic 1 (Mobile and Origins) the walk animation is always floating 1 pixel above the ground.
However, the incorrect horizontal shifting in the walk from the original game was fixed.
#SonicTheHedgehog
Deep inside the remake of Sonic 3 & Knuckles, there's a variable in the Player object that can turn on a hitbox visualizer.
It is barebones, as it only shows the Player's main hitbox. It does not show anything like Amy's hammer hitbox, or the Instashield hitbox.
There is a bit of a misconception regarding the Time Attack screen in CD93 ver0.02, where you can edit RAM to bypass the limited imposed selection to select "lost zones".
There's not actually much remnant zone data in 0.02, but the reason this happens is interesting... 🧵
So, a developer for the PC port of Sonic CD (Dino version) had joined Retro and mentioned they had an archive of a *late beta* for the PC port (v0.992). I reached out to them and have been given permission to share it for preservation!
Introducing: a quick and easy tool for combining Sonic & Knuckles with another Genesis ROM to simulate a lock-on, which you can then easily thrown into an emulator to play. Extra information is on the page itself.
Hidden Palace Zone in Sonic 2 seems to have been developed so early on that it retains data that is more compatible with Sonic 1 than Sonic 2.
**This is just speculation**, but the monitor types look to be set before the IDs were updated, and thus still use the Sonic 1 IDs.
In the remake of Sonic 3 in Sonic Origins, there exists an unused secret dubbed "Barrel Hotline" / "Hotline".
the sound test code does not exist, but general code for the secret does.
When active, it changes the barrel behavior to the original Sonic 3 behavior!
The other error messages aren't as amusing. I will note that the game will only be playable in the event that the Backup RAM is full. The other errors just freeze at the message.
In the quoted tweet, the reason the sprite looks bugged is because another object's graphics overwrite it in VRAM. However, this is not the case in act 3. However, due to a bug, this object in the 510 prototype uses the wrong tile ID for the sprite. Here it is fixed.
For those Chaotix and 32X nerds out there, I have released a disassembly of Chaotix. Unfortunately, it is very incomplete, because I don't have the time to finish it, but it does build bit perfect, and the 68000 code can be modified without issue.
There is an unused swing object (0x29) in v0.02. While not placed in a stage, its graphics do get loaded in act 2 around the area where a swing is placed in the final.
Starting from Sonic 1, when you jump after rolling, you cannot move left or right? Turns out, it might be because of the fact that when you press left or right when in the air, a speed cap kicks in, which destroys your momentum if you were rolling down a hill and then jumping.
According to symbol data found in the Gems Collection version, the name of the function that removes animals when there's a bad future from the source code is called "friend_suicide", and the function that removes badniks when there's a good future is called "enemy_suicide".
So, jumps like this are possible in the original version, but not in the remake. What gives? Turns out, it's due to a subtle difference in the order of which movement and collision handling is done that affects how jumping works.
In the 510 and v0.51 prototypes, there is an unused object that looks like beam. Touching it in 510 does nothing, but touching it in v0.51 deactivates it.
Sonic 1 also features this same speed cap for the camera... except that they forgot to put in the check for when the camera moves left, which means you can cause these same graphical corruptions in stock Sonic 1 if you move fast enough. This was fixed in Sonic 2.
Sonic 2's camera is known for lagging behind Sonic when he's moving too quickly. The reason that happens is due to the stage renderer only being able to draw directly where the camera is at, regardless of how far it has moved. Areas that should have been drawn to get skipped.
In CD93 prototype 0.02, there is an unused object in TITLE_.MMD that flashes "PRESS START", which would have presumably taken the temporary menu's place in an earlier build.
Every time you duck, Knuckles' animation will reset. This seems to actually be an oversight stemming from a half-implemented check. Before checking those conditions, it checks if a flag is set, and if it is, then it skips the other checks. However, that flag never gets set.
The points chaining system in the 2011 remake of Sonic CD is bugged. This is due to the fact that the chain doesn't get updated until a points object disappears, causing an inconsistent points chain if you rack them up too quickly.
In the original Sonic CD, the Stardust Speedway lights have 2 settings: dim and bright. Dim lights display their sprite for 1 frame every 4 frames, and bright lights do the same, but every 2 frames. [1/2]
The 1996 PC version of Sonic CD adds additional code in the floor collision function that fixes a slight visual and physics bug for when you're on a flat surface, but the left sensor is detecting a block with a steep enough angle [thread]
So, a developer for the PC port of Sonic CD (Dino version) had joined Retro and mentioned they had an archive of a *late beta* for the PC port (v0.992). I reached out to them and have been given permission to share it for preservation!
Bonus fun fact: if you look closely at the time warp image, you can see that the parts of Sonic that are supposed to be black are set to *green* for whatever reason.
There are instances where Sonic's palette uses a more saturated blue compared to his in-game palette. This particular palette comes from a potential prototype palette from Sonic 1's development found in some digitizer files.
So, in most of the stage files of the Sega CD version, there are 2 unused sets of stage layout data.
They are layouts for Green Hill Act 2 and 3 from Sonic 1.
In between v0.02 and 510, before the background was changed to the final one, the palette was slightly altered to make the sky a little less saturated. This palette data can be found leftover in the final game.
(Left = v0.02, Right = Alteration before 510)
However, James Brown is Dead is actually sampling the ending synth from "So Fine" by Electric Light Orchestra, particularly at the point where it starts pitching down.
Sonic CD still retains the code from Sonic 1 that shrinks Sonic's object collision hitbox if he's ducking... except that they forgot to update the sprite frame ID. As a result, it doesn't work as intended, and the hitbox will shrink when an angled walking sprite is displayed.
Within the various Sonic Mania leftovers in the remake of Sonic 3 & Knuckles, parts of code for Chibi Players still exist.
The Player does not visually change, but certain aspects do, such as the player getting chibi physics upon spawning in with the "chibi flag" being enabled.
They also shared the library, documentation, and sample files for Dino, found in this earlier archive they shared (that had an incomplete rip of the Sonic CD disc).
The 2011 remake doesn't accurately handle ring bonus chaining when hitting multiple ring UFOs in a row. The original uses a separate counter that doubles for each ring UFO destroyed and gets added to the ring count. The remake simply doubles the ring count.
Bonus fact: the speed cap of 16px/frame for rolling only applies horizontally, NOT vertically. This is why this particular example only has problems when the camera moves up or down.
Sonic 2's camera is known for lagging behind Sonic when he's moving too quickly. The reason that happens is due to the stage renderer only being able to draw directly where the camera is at, regardless of how far it has moved. Areas that should have been drawn to get skipped.