Sonic & Knuckles (0)

Overview
Sonic & Knuckles is a 2D action platformer developed by (with assistance from , which would be the last Sonic game they contributed to) and published by for the on October 18, 1994.
The direct sequel to , Sonic & Knuckles continues the story of , who must venture deeper through to track down (whose orbital weapon, the , crashed back down to the floating island). Along the way, he is still being pursued by who, still believing that Sonic is planning to steal the island's , hinders his progress and is still hiding the around the floating island.
While is no longer a playable character (or companion), players can now play through the game as Knuckles (previously only playable in Sonic the Hedgehog 3's Competition Mode), in which he is less agile than Sonic (and cannot use the special jumping powers of elemental shields), but has the unique abilities to , , and punch out certain obstacles (as well as having to face more difficult boss battles as an added challenge). He has his own side-story, taking place after the main campaign, in which a surviving badnik (the ) takes Dr. Robotnik's place in finding the (though it is not sure, until the end of the game, who the is).
Sonic & Knuckles is the only Sega Genesis game to utilize special "lock-on technology" (in which the features its own Sega Genesis cartridge slot at the top, similar to the accessory), so that the game can access data from certain other Genesis games. This allows players to play through as Knuckles (complete with his unique abilities), and allows players to combine both Sonic the Hedgehog 3 and Sonic & Knuckles into one "complete" game with special features.
Ports and Compilations
The game was later ported (alongside Sonic the Hedgehog 3) by Sega to (running Windows 95 and up) as Sonic & Knuckles Collection (published by Sega for Japan in 1997 and for North America in 1999). The game retains the same gameplay as the Sega Genesis version, but the music was re-done in format. It also includes the option to play Sonic 3 & Knuckles (both games locked-on) and also includes a Sonic-themed screensaver.
Sega compilations that include both Sonic & Knuckles and all of its lock-on functionality (as separate modes) include (on July 31, 1997 for the ), (on November 10, 2002 for the ), and (for the and on November 2, 2004 and for the PC on March 9, 2007). (for the and on February 10, 2009) includes the game but none of the lock-on functionality. Sonic Classics Collection (for the on March 2, 2010 in Europe only) includes the game and both the Sonic the Hedgehog 2 and Sonic the Hedgehog 3 functionality.
The game has been ported and digitally released on the (via on September 9, 2009) and (via on February 15, 2010). Both releases are programmed so that if the owner has downloaded this and any of the three Sonic games originally required for lock-on functionality, he/she can play that Sonic game as if it was going through the Sonic & Knuckles lock-on technology.
Gameplay
In Sonic & Knuckles, players control either or as they navigate through 6-8 levels (known as "Zones", split into different "Acts") to track down (in Sonic's campaign) or the lone (in Knuckles's campaign). Players must dodge dangerous obstacles (such as spikes and bottomless pits) and plow through enemies (with attacks such as the rolling jump) to reach the end of each Act.
Zones
Like Sonic the Hedgehog 3, each main level (known as Zones) are split into two unique sections (known as Acts), each act with a unique setting (such as Sandopolis Zone starting out in the vast desert and ending up inside a haunted ) and music. The first act ends with one or more to fight and the second act ends with a to fight.
Hidden Palace Zone and Sky Sanctuary Zone have only one "act" and both serve as two "acts" to one "level". Both are heavily shortened and modified for Knuckles's campaign (the first as a simple transition and the second as the Knuckles's final boss battle). Death Egg Zone and Doomsday Zone cannot be played as Knuckles. Doomsday Zone can only be played as Super Sonic (or Hyper Sonic in Sonic 3 & Knuckles) and has only one "act", serving as the Sonic's final boss battle.
In Sonic 3 & Knuckles, all of the Sonic & Knuckles levels appear immediately after all of the Sonic the Hedgehog 3 levels.
- Mushroom Hill Zone
- Flying Battery Zone
- Sandopolis Zone
- Lava Reef Zone
- Hidden Palace Zone
- Sky Sanctuary Zone
- Death Egg Zone (Sonic Only)
- Doomsday Zone (Super/Hyper Sonic Only)
Lock-On Technology
Using the game's special "lock-on technology", players can access special modes and features by putting any Sega Genesis cartridge on the cartridge's additional cartridge slot.
Booting up the game without any cartridge locked-on plays Sonic & Knuckles normally. With most cartridges locked-on, the game shows up a special "No Way!" screen (in which players can play a secret random pre-generated Special Stage by pressing all buttons simultaneously).
Blue Sphere
With locked-on, one of the message in the "No Way!" screen changes to "No Way?" and pressing all buttons simultaneously unlocks a deeper Special Stage game (known as "Get Blue Spheres!" or, retroactively, as "Blue Sphere"). Players can play a series of pre-generated Special Stage levels (up to 134,217,728 configurations of varying difficulty) and keep track of their progress using a 12-digit numerical .
Earning a "Perfect" in the stage (by collecting all possible rings) skips ahead 10 stages. Players start at level 1 and can change the password before entering the stage (including passwords given out after completing a Special Stage with any other cartridge).
There were plans to make Knuckles playable in Sonic the Hedgehog, but the concept was later scrapped because of issues with Knuckles's abilities in the game's levels.
Knuckles the Echidna in Sonic the Hedgehog 2
With locked-on, players can play Knuckles the Echidna in Sonic the Hedgehog 2, in which they can play through the entirety of Sonic the Hedgehog 2 as Knuckles. Knuckles retains all of his abilities, and the game adds some new hidden items (that makes use of Knuckles's abilities). Two-player mode (including Time Trials mode) is disabled.
Sonic 3 & Knuckles
With locked-on, players can play Sonic 3 & Knuckles, which combines both games into one "complete" game (with the Sonic the Hedgehog 3 campaign leading to the Sonic & Knuckles campaign in one long story). With this setup, players can play the Sonic the Hedgehog 3 campaign as Knuckles (complete with branching paths, due to his abilities, and a harder EggRobo boss at the end of each zone), play through the Sonic & Knuckles campaign as (or as Sonic with Tails), and save their progress in the Sonic & Knuckles campaign (complete with more save slots).
In addition, players who reach the Sonic & Knuckles campaign with all seven Chaos Emeralds can trade them for the ability to collect seven Super Emeralds (Chaos Emeralds powered-up by the Master Emerald). When they have all seven Super Emeralds, they can into Hyper Sonic (who, in addition to the abilities as Super Sonic, gains the ability to perform a mid-air dash that flashes the screen, clearing all enemies on the screen), Hyper Knuckles (who, in addition to the abilities as Super Knuckles, triggers a earthquake when clinging on to a wall, clearing all enemies on the screen), or Super Tails (who has the abilities of Super Sonic as well as being surrounded by four super-powered that automatically charge at enemies on the screen).