Sonic & Knuckles Collection

Sonic & Knuckles Collection is a PC compilation of Sonic the Hedgehog 3, Sonic & Knuckles, and Sonic 3 & Knuckles with MIDI music and new compositions for some Sonic 3 levels.

Level Select
Go to Angel Island 1, grab onto a swinging vine, and press Left, Left, Left, Right, Right, Right, Up, Up, Up. A ring sound will play if you did it right. Press ALT + R to reset the game and from the title screen press Up to reveal "SOUND TEST" and press Enter. Press Numpad 3 to change your character.

The method of unlocking the level select in Sonic 3 & Knuckles apparently works in Sonic 3 alone (a good thing, too, considering it's a lot easier to unlock this way) though debug mode won't be unlocked along with it and you can select any Sonic 3 zone as usual (but not Flying Battery, Mushroom Valley, Sandopolis, or Bonus).

Debug Functions via S3K.ini
Though you can enter the debug menu code in-game, you cannot use any object placement functions as controls are limited to four directions and a single key for jumping. However, you can properly enable it by creating a file named "S3K.ini" in your C:\WINDOWS directory (where C:\ is the main partition used for Windows) and typing the following into the file:

[Debug] DebugMode=1 EnableFrameDrop=1 MukaiDropFrame=0 ShowFrameCount=0 EnableFrameCapture=1 UseModeX=1 NoSoundEffect=0 CDCheckEnable=1 SonicGameMode=0 BGMMode=2 GameMode=0 LangMode=0

Here's what each of these functions do. Note also that generally "1" means the option is enabled, while "0" means that it is disabled:
 * DebugMode - "1" will fully enable debug mode. When you load up any of the games, you'll start at the level select screen instead of the Sega logo. From there, just select any level and it'll be turned on automatically. As with the console versions you get unlimited time, a coordinates display, a sprite counter, and invincibility. When debug functions are enabled, the numeric keypad is mapped to the three buttons on a Mega Drive/Genesis controller, so make sure you have NumLock turned on.
 * Press Numpad 1 to reverse gravity.
 * Press Numpad 2 to toggle object placement mode.
 * In object placement mode, press Numpad 1 to move forward one object.
 * In object placement mode, hold Numpad 1 and press Numpad 3 to move backward one object.
 * In object placement mode, press Numpad 3 to place the selected object.
 * EnableFrameDrop - Sonic & Knuckles Collection is broken in windowed mode on computers with a CPU faster than 350MHz because it lacks a speed-limiting feature in this mode. However, the timings used by full screen mode are based on the monitor's refresh rate, so the game can be played at the correct speed at a 60Hz refresh rate on any modern system. Set this to "1" and you can play in windowed mode at a perfectly playable speed.
 * MukaiDropFrame - Basically functions in the reverse fashion of EnableFrameDrop. Leave this one turned off.
 * ShowFrameCount - Displays the FPS in-game when enabled. This will obstruct the game screen, but if debug mode is turned on then the game screen will be shifted down the window to allow the FPS counter to display without covering anything up.
 * EnableFrameCapture - "1" allows you to take a screenshot of the game screen at any time by pressing F9. Screenshots are saved as "Cap(5-digit_number).bmp" in the game's directory.
 * UseModeX - Toggles Mode X on or off.
 * NoSoundEffect - Toggles whether sound effects will be disabled.
 * CDCheckEnable - Toggles whether the game will check for the S&K Collection CD-ROM. "0" will allow you to play without having to insert the CD!
 * SonicGameMode - Specifies which game will be loaded if "SONIC3K.exe" is directly launched in Windows. "0" loads Sonic 3 & Knuckles, "1" loads Sonic & Knuckles, and "2" loads Sonic 3.
 * BGMMode - Specifies which music setting will be used. "0" disables music, "1" uses FM synthesizer music, and "2" uses general MIDI music.
 * GameMode - Specifies which mode the game will start up in. "0" is the full version, "1" is demo mode, and "2" is trial mode.
 * In demo mode, all controls are disabled so only the title screen and rolling demos can be viewed. Used for demonstration purposes.
 * In trial mode, only the single-player mode of Sonic 3 & Knuckles can be played, and only Angel Island Zone is playable without saving. After clearing Act 2, the game ends with a dialog message, then returns to the title screen.
 * LangMode - Specifies what language the game will use. "0" is English, "1" is French, "2" is German, and "3" is Spanish.

Knuckles in Sonic 3
Sonic 3 had leftover code for Knuckles, who was planned to be a playable character in the game, but when he was selected you controlled Sonic instead. Because the PC version of Sonic 3 has the S3&K coding (including fixes to bugs that were originally present in the Genesis version of Sonic 3), Knuckles is fully playable in Sonic 3 alone!

To play as him, you need to use an external save editor (like this one) to modify "SONIC3K.bin" and create a save file in Sonic 3 with Knuckles as the chosen character, then you can play as him in Sonic 3. Because Knuckles (and Flying Battery) was planned for and still has existing data in Sonic 3, he is a selectable value in editing saves.

Unfortunately, because only the Sonic/Tails boss triggers are in place, Knuckles cannot finish Angel Island 2 and Launch Base 1...but his bosses for Angel Island 1 and Marble Garden 2 are in place (they weren't there in the Genesis version). As Knuckles' Launch Base 2 bosses are absent, he must glide over to the Sonic/Tails boss area from his own and fight the final bosses.

After defeating the bosses and watching the Death Egg explode, the game will crash since Knuckles never had an ending programmed for Sonic 3 alone.

Flying Battery Zone in Sonic 3
Like with Knuckles, Flying Battery Zone is playable in full form and you can access it. Use an external save editor to make a Sonic 3 save which is set to start at "Zone 5" – Flying Battery, complete with unused Sonic 3 data select icon.

Flying Battery is the same as Sonic 3 & Knuckles, but in Sonic 3 it's sort of an odd stage, because once you clear it and reset the game will advance you to the "true" Zone 6, which is Ice Cap. Continuing to play the game after this will allow you to play through the remaining Sonic & Knuckles zones in Sonic 3 mode starting with Sandopolis. Clearing these zones will give the player the normal Sonic 3 & Knuckles credits/ending based on how many Chaos Emeralds you have, but when you get back to the data select screen the palettes turn pink for some reason, and the save file you used will be redirected to Marble Garden for some stranger reason.

Further, once you beat Flying Battery, it can't be accessed again unless you create another file that can access it.

Unused Music


Track #44 in the sound test, which is normally reserved for the Sonic 3 minibosses in the Genesis version, plays an entirely different song that isn't used anywhere in the game (this version of Sonic 3 uses the S&K miniboss theme).