Sonic & Knuckles Collection is a Sonic the Hedgehog compilation game for Microsoft Windows-based PCs.
The ports have all of the music emulated in MIDI format. Some music (Carnival Night Zone, IceCap Zone, Launch Base Zone, Knuckles' theme, the Sonic 3 Credits theme, the sub-boss music from Sonic 3, and the Competition main menu) was replaced with original music. One possible explanation for this is that the pieces of music from the Genesis version used sound effects not contained within the general MIDI standard, and many sound cards at the time of release did not have the capability to play additional samples along with the MIDI. Another explanation for the replacement is that the songs were replaced due to legal reasons, because connections could be made between similar songs by Michael Jackson. Other than that, the gameplay is identical to their Mega Drive / Genesis counterparts.
This game is virtually impossible to play in windowed mode on any system with a CPU faster than 350 MHz, because the game does not have proper speed-limiting routines in this mode. However, the timings used by the game are based on the monitor's refresh rate. Switching the game to fullscreen mode lets the game play properly, no matter what your system speed is. In windowed mode, the game can be played at the correct speed whenever the screen refresh rate is at 60 Hz. Sega has also provided a patch to fix this problem without reducing the refresh rate.
Blue Sphere (in options dialog as "Special Stage Mode")
The European and North American versions of the collection also includes Sonic the Screensaver which the player can customize Windows with Sonic themes, wallpapers, icons, and music from Sonic 1, 2, 3 & Knuckles, and the Japanese soundtrack of Sonic CD in 11 kHz WAVV format. However, in Japan, Sonic & Knuckles Collection and Sonic the Screensaver were released separately on the same day.
The sound test was featured in the options mini toolbar for the game, because a glitch would occur and the game would reset if the player tried to listen to a song.
Mushroom Hill's Act 1 music had the beginning sound removed for this compilation.
A song was included in this compilation that does not exist anywhere else. It's unknown if it was meant to replace a song from the console versions or not. The song also bears some resemblance to the theme of "Green Hills Zone" and its vocal counterpart, "Sonic - You Can Do Anything" from the Japanese/Euro Sonic the Hedgehog CD soundtrack.
Angel Island Sonic in Knuckles': To do this glitch you need Tails. Have Tails carry Sonic up then stop flying. If you have Hyper Sonic, you can double jump through the dirt. You can skip the Mini-boss if the game is Sonic 3. NOTE: If the game is Sonic 3 & Knuckles you are fighting 2 Robotniks.
Marble Garden Bypass Mini-boss: Spindash in the boss room, but don't go too far. Now Screen Scroll Glitch. The minute you do the Screen Scroll Glitch, Hold right. You just bypassed the Mini-boss! You can also fight Robotnik in a Special Stage Room.
Carnival Night Underwater: Get to the place where Knuckles shuts the lights off. Then have Tails lift the barrier you just went through. Keep on going backwards and... You're in Carnival Night Underwater!