Sonic Advance 2 was released on December 19, 2002, in Japan and on March, 10, 2003, in the U.S. This was the second game on the Gameboy Advance system with Knuckles as a playable character. Just like Sonic Advance, this game is very similar to the 2D games from the Genesis/Megadrive. The main new feature is the R-tricks that allow Knuckles (or any character) to jump higher, move farther, or quickly change direction. You will need to use the R-tricks to get to certain places within the game.

UNLOCKING KNUCKLES

Knuckles is the last main playable character to be unlocked. Knuckles can only be unlocked by beating Knuckles (the boss of Sky Canyon) in Sonic's game.

KNUCKLES' GAME

Knuckles is somehow tricked into thinking Sonic will do something bad (that is why Knuckles is a boss in Sonic's game). After learning otherwise, he will try to help out: now you can play Sonic Advance 2 over with Knuckles instead of with Sonic, Tails, or Cream & Cheese.

KNUCKLES' ZONES

Each zone has two acts and a boss, except for the last one, XX. XX contains all the bosses from the previous zones and one final boss that is unique for the zone.
Leaf Forest (picture)
Hot Crater (picture)
Music Plant
Ice Paradise
Sky Canyon
Techno Base
Egg Utopia
XX

POWER-UPS

1-Up: Gives an extra life
5 Ring: Worth 5 rings
10 Ring: Worth 10 rings
? Ring: Worth a random amount of rings
Electric Shield: Attracts rings and prevents Knuckles, Sonic, Tails, or Cream from losing their rings for one time when either hit by an enemy or falling into a trap
Green Shield: Prevents Knuckles, Sonic, Tails, or Cream from losing their rings for one time when either hit by an enemy or falling into a trap
Invincibility: For a short time, nothing can hurt Knuckles, Sonic, Tails, or Cream
Sneakers: Increase Knuckles, Sonic, Tails, or Cream's speed for a short time

SPECIAL STAGES

This is where you obtain chaos emeralds. In every act there are special rings with stars within them. You have to collect seven of them and make it to the end of the act without dying to get to the special stage. In the special stage, you must avoid Zero (from Sonic Adventure) while collecting the required number of rings. There is only one chaos emerald per zone (not counting XX which doesn't have any acts) so you have get through at least one act for each different zone to collect all 7 chaos emeralds.

BONUSES

1 character collects 7 chaos emeralds = unlocks the Tiny Chao Garden
2 characters collect 7 chaos emeralds = unlocks the Sound Test
3 characters collect 7 chaos emeralds = unlocks the Boss Time Test
4 characters collect 7 chaos emeralds = unlocks Amy Rose as a playable character
Whenever Sonic collects 7 chaos emeralds the true final stage will be unlocked, which will be played by Super Sonic.