Sonic the Hedgehog 2 (16-bit) bug list

Player bugs

Super Sonic at the end of a level

The Super Sonic glitch in action

Attempting to transform into Super Sonic after hitting a signpost or prison capsule results in Sonic "walking" in mid air, and becoming unresponsive to controls. If Sonic moves off the right side of the screen before this happens the score tally will appear and the game continues on to the the next level as normal. If he does not leave the screen he will get stuck with no way of ending the level. The player can't wait for a time over, because passing a signpost stops the timer. The only thing to do without debug in this situation is to reset the game. This shows the glitch.

Note: Prison capsules make the score tally appear automatically, so the level will always end.

Fixed in: Rev.02 (Sonic Classics)

Tails high score

If Tails hits an enemy after Sonic has just died, he gets stuck and gains a large score (as well as several extra lives). [1]

This bug occurs in all known betas and prototypes; an easy way to reproduce it in the Wai beta is to go to Hidden Palace Zone, immediately Spin Dash to the right, and press jump as Sonic dies.

In the final, the bug still exists, but Tails starts flying when Sonic dies, making him unable to hit enemies.

Fixed in: Rev.00

Super Sonic countdown

The timer that keeps track of the ring countdown is flawed in that it cycles every 61 frames instead of 60. This effectively gives the player an additional second of time for every 60 rings.

Not fixed in any version

Life counter glitch

If a player dies from time-over in a 2P Versus mode while on their last life, the Game Over routine will be interrupted and the results screen will be displayed. The player who died will appear to have 0 lives, but if they die again, the counter will roll back to "y5" (255), as the lives are stored as an unsigned byte, and the life counter was only meant to display up to 99 lives.

This bug can also be found in single player mode. In Chemical Plant Zone, there is an area before the boss where there are spikes underwater. If a player has 1 life, gets a ring and lets the drowning timer dwindle down to "1", then jumps into the spikes, Sonic will drown in the middle of his "recoil from damage" animation, which will cause two lives to be lost and the counter to roll back to "y5".

Not fixed in any version

Multiple Badniks in a row in 2-Player mode

The shared combo counter glitch in action

It's quite common knowledge that if you destroy several badniks in a row you're awarded more and more points.

However, this behaviour is present also in Sonic 2's 2-Player mode, and the counter of destroyed badniks is shared between the players. Example: If Sonic destroys a badnik, and Tails quickly destroys another badnik, Tails will get 200 points, and vice-versa. First noticed here.

Not fixed in any version

Knuckles in Sonic 2 signpost glitch

In Act 1s, if you glide past the signpost instead of walking past it, the screen doesn't lock and Knuckles can move around at will during the score count. Here is the glitch.

Not fixed in any version of Knuckles in Sonic 2.

Level bugs

Emerald Hill Zone

Horizontal scrolling glitch

In Emerald Hill Zone, the bottom two rows of foreground pixels don't scroll horizontally, causing them to be permanently misaligned.

Not fixed in any version of plain Sonic 2; Fixed in Knuckles in Sonic 2.

2P: Bridge sprite glitch

Bridge sprite glitch.

In 2P VS mode, if you go on the top route to the section where there's two bridges right next to each other and move the camera such that only four or fewer logs from the first bridge are visible, the entire first bridge will disappear. The bridge will reappear if you move to the left again.

Not fixed in any version.

Chemical Plant Zone

Should you get knocked into a transportation pipe by getting hurt, The pipe will glitch As seen here

Not fixed in any version.

Aquatic Ruin Zone enemy collision

In Aquatic Ruin Zone, if Sonic touches an enemy while he's in a section of the level that is obscured by leaves, no collision will occur.

Not fixed in any version.

Sonic gets hit by a Grounder, but nothing happens!
Disabling the scroll plane to get a closer look.

Hill Top Zone

Rexon Crash

On Hill Top Zone, it is possible to crash the game when hitting Rexon (the plesiosaur-like badnik that sits in the lava). Conflicts in the code cause it to jump to a section of code it was never meant to jump to. This results in invalid opcodes being processed and an eventual crash. A link to this glitch is here (the player here is Super Sonic but it can happen as regular Sonic as well).

Not fixed in any version of plain Sonic 2; Fixed in Knuckles in Sonic 2.

Super Sonic Death

When playing as Super Sonic, if he enters the area where the Rexon from above is found and falls to the bottom of the screen (where there is lava) then the camera doesn't follow him quick enough, the ring-loss chime plays and Sonic dies.

Not fixed in any version.

Oil Ocean Zone physics

In Oil Ocean Zone act 2, find the area with four green platforms which launch into the air occasionally. Step on the last one and when being shot out of the tube hold right and land on the spikes in a way that will knock you into the round object to the left. If done correctly the physics will be different and the character will jump higher. The bug eventually wears off when getting in another speed tube, jumping on a spring, or passing through a wall. Alternatively, you can use the Pro Action Replay code FFB82C:0004 while on that level. This code only works when reaching that area.

Not fixed in any version.

Metropolis Zone shortcut

By triggering the platforms that fall into the lava while invincible (even via getting hit) Sonic will ride the platform and penetrate the lava. This almost always brings Sonic into a later part of the level. With one platform that isn't far from an invincibility box, you can even get the "zero-gravity" mode.

Not fixed in any version.

Sky Chase Zone falling off of Tornado

In Sky Chase Zone, if you charge a spindash up and release, you will go too fast for the Tornado and fall off. This also happens with Super Sonic, too. This glitch can be seen in this video. Whether or not this is actually a glitch is up for debate, as it could just be seen as a mistake on the player's part.

Not fixed in any version.

Wing Fortress Zone walking on air

In Wing Fortress Zone, find a column of platforms that rise up and then retract. Stay on one of the platform as it reaches the top and retracts. You won't fall down and instead will be standing in mid-air. You can walk left and right at that height and won't fall down until you get hit by an obstacle or jump down.

Only present in Sonic Classics version of Sonic 2

Miscellaneous bugs

14 continues chime

When the 14 continues cheat is performed by playing sounds 01, 01, 02, and 04 on the options menu, an invalid sound attempts to play, resulting in non-stop Oil Ocean music for the remainder of the game. The fault is with the way the sound number is entered into the game's code. For every sound, the bit 7 must be enabled to properly reference it. The code instead is written without bit 7 being used.

Fixed in: Final Revision 02

Music tempo change

If the 1up jingle is playing while the super sneakers wear off, the level music will not revert back to its normal tempo.

Not Fixed In Any Version

Unlimited speed shoes

If a player dies whilst using speed-shoes in 2 player mode, the character's speed level isn't reset properly, thus causing the character to run at speed-shoe speed for the remainder of the act.

Not Fixed In Any Version

Super Sonic keeps invincibility stars

When transforming into Super Sonic, if Sonic collects his 50th ring and jumps while invincible, the invincibility stars will not disappear after 20 seconds as expected. Since Super Sonic is already invincible, the stars don't give him any additional powers.

Super Sonic with stars left over from a previous invincibility monitor.

Not Fixed In Any Version

Pink Title Card Bug

Whenever a zone title card starts, you will see a pink flash.

Not fixed in any version

Passed Star Post

First, go to a special stage regularly. Then go to the Star Post on a small island (use a spring to get up) and you will see that it has already been lit, and you didn't pass it at all.

Super Sonic in 2 Player Mode

If you get all the chaos emeralds (doesn't matter if you use the cheat code or get them manually), go to the title screen, go to the OPTIONS menu, then press Start while on the VS MODE ITEMS option, 2 player mode will start and Sonic can turn super, though he has glitched graphics. The animation frames regular Sonic has (like looking up or jumping) are unaffected.

When you die, you'll come back as super sonic with zero rings, giving you about 1 second to remain "super". Before Sonic's camera catches up to his respawn point, you can also use the other player to see Super Sonic just standing there.

If you make Sonic turn super and hit a teleport monitor, Sonic will turn back to normal, and Tails will inherit several 'super traits', effectively becoming "Super Tails": He has no flashing palette or trailing stars, but he does inherit Super Sonic's speed and invincibility. He also gains invincibility stars.

The game will only reset your emeralds to 0 when you select 1 or 2 player from the title screen. You can get the emeralds with one character, go to the OPTIONS menu, select another character, and automatically have the chaos emeralds.