This article has a talk page!This page details bugs of Sonic Advance (Game Boy Advance).
Tiny Chao Garden Ring Debt#
The original released versions of the game in all regions have a rather severe bug:
An address keeps track of the total amount of rings collected in the main game. When accessing the Tiny Chao Garden, the value in the address is read and stored by the Tiny Chao Garden to keep track of the ring count. When deleting the save data, the value gets erased.
As a result, rings collected in the main game will no longer transfer to the Tiny Chao Garden until the total amount of rings collected in the main game matches that of the value stored by the Tiny Chao Garden prior to the save being deleted. This was fixed in the various double pack releases containing Sonic Advance and the Japan only v1.1 by not erasing the ring total when deleting the save data.
Grind Rail Desync#
In Neo Green Hill Act 1, there is a rail at the top of the stage about halfway through that Sonic can grind on. If one lands on the rail with high enough speed and continues to hold forward until Sonic falls off the rail, he will be put in a strange state where he no longer interacts with the ground but can land on certain foreground elements and objects. The state can't be interrupted once entered, and without an object to stand on, Sonic will fall through the ground and lose a life.
This was not fixed in any version of the game, and even seems to persist in its sequels, though it is much harder to trigger there.
Ultra Spin Dash#
To account for the lack of jump buttons available in Sonic Advance compared to the Genesis entries (1 vs 3), the number of button inputs required to fully charge a Spin Dash was decreased from 6 to 2. As a seeming side-effect of this change, should one charge up the Spin Dash 12 times within 12 frames, 1 button input each frame, the Spin Dash will become so fast it makes your character disappear from view immediately, causing the camera to swing wildly left or right to catch up. The state one is put in from this can be used to go through walls and wrap around the level.
This glitch is effectively impossible to perform with human reaction time, hence it can only be seen using emulator tools.
Cosmic Angel Gravity Desync#
In Cosmic Angel, there is an S-shaped set of ramps partway through the level lined with spikes that the player traverses under reversed gravity. If one Spin Dashes and jumps down the second ramp and lands at a certain spot near the spikes, you will clip through the floor. This allows the player to explore the level while still under reversed gravity in unintended areas. As Tails, it is possible to fully explore the level in this state and even reach the boss with his flight ability.
X-Zone Softlock#
This glitch requires the use of the "Sonic & Tails" mode accessible with a code. In the X-Zone level, if Sonic gets caught in the Egg X's grab attack and Tails lands the last hit on the boss at the same time, Sonic will be stuck in the grabbed state, unable to trigger the end cutscene and credits.