Sonic the Hedgehog 3 & Knuckles/Bugs
From Sonic Retro
Contents
Level bugs
Move during end of level score tally
If a player times it right and jumps into Tails hands as he is flying at the end of the level the player will still be able to move during the score tally.
Not fixed in any version
Flying Battery Boss
While playing as Knuckles, in Flying Battery Zone act 2, the boss is Robotnik instead of Egg Robo.
Not fixed in any version
Mushroom Hill Boss
The same thing sometimes happen in Mushroom Hill Zone act 2, though not always. It happens more often after the player dies.
Not fixed in any version
Knuckles in Carnival Night
While playing as Knuckles, one can take Sonic's path in Carnival Night 2, then glide over the boss area revealing a load of junk.
Not fixed in any version
Knuckles Palette
Due to palette limitations, Knuckles' socks change colors; when you are playing as Knuckles, they are green. When you are playing as Sonic, Tails, or Sonic and Tails, they are yellow. Furthermore, as can be noted by entering Sky Sanctuary Zone act 1 as Knuckles through cheating, the two 'versions' of Knuckles have slightly different hues.
Not fixed in any version
Standing on LBZ spinning floors
If the player comes to a natural stop on the spinning floors after being rolled up into a ball, he will be using his standing sprite instead of the rotating sprites.
Not fixed in any version
Triggering the LBZ booster infinite times
If the player does a spin dash in the right place and at the right time he will trigger the booster infinite times as long as he'll mantain his spin dash position.
Not fixed in any version
Hovering Knuckles in Hydrocity
If you climb in Hydrocity Zone below one of those up and down moving rotating blocks, it will push you down without resetting you to normal status when you leave the wall, resulting you are flying in the middle of nowhere. This video might explain it a little bit better.
Not fixed in any version
With Hyper Sonic...
Hyper Sonic's extraordinary abilities help to bring even more bugs and glitches into Sonic 3 & Knuckles. In particular, his double jump which allows him to boost towards any of the 8 main directions can bring quite a lot of confusion to the mix.
Mushroom Hill boss
By double jumping before the screen gets locked vertically, Hyper Sonic messes up the level scrolling. The level is still completable, though.
Not fixed in any version
Flying Battery
Hyper Sonic's ability to cross small walls and barriers with a double jump allows him to escape from the force field in the pre-boss in Flying Battery 2.
Not fixed in any version
Mushroom Hill miniboss
If MHZ's miniboss is defeated too quickly (e.g. while it is still moving before it could arrive to the right limit of the screen), the Act 1 to Act 2 transition doesn't take place properly, leaving Sonic helplessly stuck at the beginning of Act 2. In order to hit the miniboss 6 times so quickly, Hyper Sonic's double jump must be used.
The score tally already doesn't look so good
Hmmm, last time I checked there used to be a slope there
Good, Knuckles won't come to perform the cutscene. Gotta wait 9 minutes and 59 seconds...
Not fixed in any version