Sonic the Hedgehog 2 (Mega Drive)/Diferenças entre Revisões

This is a sub-page of Sonic the Hedgehog 2 (Genesis)/Revision Differences.

Sonic 2 contém várias diferenças regionais e revisionais, às vezes com base em revisões "anteriores". Das muitas, as três principais são a Revisão 00, a Revisão 01 e a Revisão 02, que se chamarão apenas REV00, REV01 e REV02 a partir de agora.

Código de Mudança de Região

Na tela de título, pressione 'Cima, baixo, baixo, baixo, cima, e um som de anel será ouvido. Isto muda o jogo entre o modo japonês e o modo internacional, como se o jogo fosse colocado em um console japonês. No modo japonês, as referências a "Tails" são mudadas para Miles (seu nome oficial no Japão), e os símbolos da marca registrada são removidos da tela da Sega e a tela de título. Pode ser reentrado para reverter para o modo internacional. Funciona da mesma forma no hardware japonês (mas obviamente é o contrário).

REV00 and REV01

The first two retail releases, being compiled on September 26th and September 29th respectively and with REV01 being the most mass-produced version.

REV00	REV01

• The signpost in Casino Night Zone is a little too deep into the ground in REV00, resulting in the bottom portion of the goalpost being visible through the floor.

• The developers forgot to add a ring cap to monitors in REV00, meaning 999+ can be collected, bugging out the ring counter.

REV00	REV01

• Thomas Kalinske (Sega of America's president at the time) was misspelled as "Tohmas Kalinske" in REV00. REV01 fixed his typo, however they forgot to fix Phoenix Rie (Rieko Kodama) being misspelled Phenix Rie.
• REV00 forgot to set the 'remember state' flag for checkpoints in Wing Fortress, meaning dying will make them all look activated.

• Sonic and Tails briefly display garbled art after activating a Teleport Monitor in 2-player mode. This seems to be the result of both players using the other players' tilemap but applied to their own graphics. REV01 fixes this by making the players invisible until they start moving again.
• The yellow spring walls in Metropolis Zone can be bounced on while hurt in REV00, which freezes the character's animation and locks the controls.
• If the big Casino Night Zone springs are landed on while hurt in REV00, the character enters a glitched state: they don't enter their rolling state, and remain able to walk, but are still treated as if they're attached to the spring.

REV00	REV01

• Two flippers in the 2-player version of Casino Night Zone Act 1 changed positions in REV01.
• The Crawl placement in the 2-player version of Casino Night Zone in REV01 matches Beta 8's placement.

REV00	REV01

• "Invisible wall" and yellow spring collision objects are visible in Debug Mode REV00, but not REV01.
• A slight code change was made to the routine to draw sprites (BuildSprites in the Github disassembly) in REV01 in an attempt to prevent the game from crashing if an object is placed after dying in Debug Mode. Specifically, an ID check instead points to something else instead of code that makes the game read off an odd address (which causes it to crash as the Genesis can't), however a mappings check was also removed meaning the crash still happens.
• REV01 is overall more tight, removing unnecessary stuff such as Hidden Palace's background positioning routine.

Sonic Mega Collection

The version included in Sonic Mega Collection is the REV01 version (instead of the REV02 version oddly), however it fixes a bug where the 14 continues cheat (1, 1, 2, 4 on the options menu) causes the Oil Ocean theme to continually play. This is because, despite what the sound test says, the sound IDs actually start at $80 internally, so the 2 player results would be $81 and so on. Its possible that the person programming the cheat mistook the continue jingle's sound test ID ($3F), with its actual ID ($BF), which causes the sound driver to malfunction and be unable to play any new sounds. In addition, the checksum check was removed meaning the boot time is much faster.

REV02

A third revision that never saw a standalone release, instead being used for future versions such as Sonic Classics, Knuckles in Sonic 2, the Mega Play arcade version, Sonic Jam and Sonic the Hedgehog 3. Unlike the previous two revisions, this wasn't found in the Sega QA archives.

This version fixed several major bugs including:

• A crash that would sometimes happen if Sonic defeated a Rexon in Hill Top Zone.

• The ability to transform into Super Sonic at the end of a level, which would get the player stuck in the air (and prevent the level from being completed)

• The background speed and offset variables not being reset if the player continues from a checkpoint in Wing Fortress Zone. This is only a problem if the player gets a Time Over during the WFZ ending sequence.

Additionally, some under the hood changes were made:

• REV00 and 01 had a lot of branches to "jump" commands, while REV02 removed most of these; as a result, the performance is slightly better.
• For some odd reason, most "lea" commands were changed from short-addressing to long-addressing (and no, it's not that the branches were out of reach).
• Some addi/subi commands were optimized to addq/subq.
• Random "even" commands were added in various spots for no reason.
• Even more unused code was removed including Wood Zone's level layout drawing routine, resulting in it taking awhile to draw segments of the screen.

Sonic Classics

Though it's based on REV02, the Sonic Classics release introduces several bugs:

• Grabber's legs and Mecha Sonic's flame and sparks aren't properly flipped if they're facing right.
• The player cannot Spin Dash off the Tornado in Sky Chase Zone.
• The vertical conveyor belt platforms in Wing Fortress Zone do not make the player fall when they retract into the wall, causing them to walk on air.

Knuckles in Sonic 2

Aside from the obvious addition of Knuckles instead of Sonic, there were some minor changes.

• The game now saves the player's rings after exiting a Special Stage, a la Sonic 3. However, this has the unintended side effect of allowing the player to keep their rings after death if they enter a Special Stage beforehand.
• The bottom two rows of pixels of the screen in Emerald Hill were fixed.

Sonic the Hedgehog 2	Knuckles in Sonic 2

• Object layouts were altered, mostly adding monitors and rings in places Knuckles can reach but Sonic and Tails can't.

To do: Cover everywhere that there was a change in object layouts.

• The shield and invincibility stars were changed to gray; this is because Sonic uses 4 shades of blue, while Knuckles uses 3 shades of red and 1 shade of green. However, water surfaces in Aquatic Ruin Zone weren't changed for some reason, which makes them look a bit weird.
• All of the cheat codes were changed:
  • Level Select: On the title-screen, press Up, Up, Up, Down, Down, Down, Left, Right, Left, Right then hold A and press Start.
  • Debug Mode: On the level select, play sounds 01, 09, 09, 04, 01, 00, 01, 08 (October 18th 1994, which is Sonic & Knuckles release date).
  • All Emeralds: On the level select, play sounds 01, 06, 07, 07, 07, 02, 01, 06.
• For unknown reasons, all objects except for Rings and Monitors were removed from Debug Mode, with the Monitor now being a Ring instead of the 2-Player Teleport.
• Path swappers (which are used by the engine to switch Sonic onto another plane) are now visible in Debug Mode, like they were in some early prototypes.
• Two-player mode and the options screen were removed, alongside a playable Tails.
  • As a result, all tracks linked to the aforementioned two-player mode (tracks 01, 03, 08, and 0C) are now unused outside of the sound test.
• The Tails monitor at Hidden Palace Zone now grants an extra life.

Sonic Jam

• Unlike previous versions, Sonic Jam's version of Sonic 2 directly ported the code to the Sega Saturn's hardware. As a result, the game can now use CD audio which prevents channels from going silent, and load times are reduced.
• This version also fixes the bottom two pixels of Emerald Hill Zone.
• There are three difficulty settings, Easy, Normal and Original; Easy removes a few levels and changes the object layout, Normal has all the levels but still alters the object layouts, and Original uses the original object layouts.
• There's a small bug with Chemical Plant's water palette, as the darkest purple one is even darker than it should be (appearing black).
• Instead of playing the Sonic 2 invincibility theme, Sonic Jam instead plays the Sonic 1 invincibility theme; the Sonic 2 version is on the disc, meaning it was likely a mistake by the porting team.