Sonic Adventure 2 Cheats & Tips

Unlock All charactors
At Title screen press Y Y B X A A left right start. If done correctly you should be able to choose all characters (including evil)
submitted by Peter Allen

Play as Big the cat
To use Big the cat in 2 player mode, complete all Eggman's missions with an A rank.
submitted by ZERO THE DARK STALKER

Play as Chao
To play as a Chao in 2 player mode complete all of Tails's missions with an A rank.
submitted by ZERO THE DARK STALKER

Play as Tikul
Yet another 2 player only character. To play as Tikul complete all of Knuckle's levels with an A rank.
submitted by ZERO THE DARK STALKER

Play as Amy
To play as Tikul in 2 player mode, complete all of Sonic's levels with an A rank.
submitted by ZERO THE DARK STALKER

Play as Chaos O
To play as Chaos O in 2 player mode, use him to beat all of Rouge's levels with an A rank.
submitted by ZERO THE DARK STALKER

Play as Mecha Sonic
I know it sounds to good to be true but you can only use him in 2 player mode. To unlock Mecha Sonic, complete all of Shadow's levels with an A rank.
submitted by ZERO THE DARK STALKER

Unlock the Dark and Hero gardens
To unlock the Dark and Hero gardens you must either treat your Chao very good or very badly.

Dark garden:
You must hurt or scold your chao in various ways Ex: Throw it, attack it, or jump on it. Do this repeatedly and your chao will slowly turn darker and darker until it becomes a devil (you will know this when his tail turns to a little pointy spear, and his colors are very dark, nearly black brown, and his little ball above his head is dark pink) Maintain your chao in this state by hurting it continually while feeding it animals...until it transforms then you don't have to hurt it anymore, it'll remain black. You will then have access to the Dark garden.

Hero Garden
To unlock Hero garden you must do just the opposite, excessively pet, pick up, and rock your chao until it turns white. Maintain it in this state while feeding it lots of animals until it transforms. The Hero Garden will be available.
submitted by Lucasso (luctmrc@yahoo.com)

Make your chao wear things on its head
In order to enable your Chao to wear stuff, you must first find a walking skeleton of an animal hidden in a level. There's at least two that I know of hidden in the Pumpkin Hill level for Knuckles. It is in the graveyard atop the Church Mountain. Right in front of the church tower there's a touch screen, the skeleton should be wandering about there. Feed at least three of those to your chao (You must be Knuckles or Rouge), next dig around the Chao garden until you dig up an object. This occurance is quite rare so you must do this repeatedly. Give this object to your chao and it'll put it on its head. If you hurt your chao the object will fall off, but don't worry, the Chao will always put it on again from now on. Depending on where you dig, you will find different objects. In the Chao Garden you will find a pumpkin, and ONLY a pumpkin. Same goes for the Hero Garden. But in the Dark Garden you will unearth a skull. You may also make the Chao put on the remains of the egg-shell it came out of. Have a blast! :)

Note: a young chao might not want to wear these items.
submitted by Lucasso (luctmrc@yahoo.com), ZERO THE DARK STALKER and Billy BoB

Big cat in the Opening Movie
In the opening movie when Sonic jumps out the copter start pressing A as soon as the pilot says "were en route everything's a go". Big will come out to look at sonic (I believe Big is secretly helping them... maybe he helped set sonic free... or he lost froggy again?!) as he flies down.
submitted by Jason Krispin

Properly hatch eggs
To hatch a egg the right way, you should pick it up and rock it back and forth (by picking it up and holding "B" and moving the analog stick).
submitted by Billy BoB

Ghost Chao
Give your chao lots of bats and ghost cows (any animal of the black type) after it matures. It should lose its legs and wings after a while and appear to float like a ghost!
submitted by Zero (near_perfect_chaos@hotmail.com)

Unlock Boss Mode, and Final Battle
Complete both hero and dark stories to open up the final chapter and Boss Mode on either side.
submitted by Zack and Grey

Scene Selection
Complete the game on either side.
submitted by Grey

Running instead of boarding
In the begining of the first stage, you are riding a board. After you get off the board...run as fast as you can into a wall. If you've done it correctly, then sonic should fall over. While he's still laying on the ground, pause the game and hit restart. Instead of being on the wing/board, Sonic will be running.

Note: if this doesn't work, try only pressing start once Sonic's up again(right just after lifting up) or when he is lifting himself up.
submitted by T.J. Mason and shadow_10th_ann