JP Release: December 10, 2001
NA Release: February 12, 2002

STORY

Considering this was a port of the Dreamcast's Sonic Adventure 2, most of the info in that section is accurate for SA2B. So check that page for the levels/power-ups, etc.

2-PLAYER MODE & EXTRA STUFF

2-Player Mode

It's Knuckles vs. Rouge vs. Tikal vs. Chaos 0 in a best of 3 to find Master Emerald shards. You play in any of Knuckles or Rouge's stages from the game. The first to find 2 shards out of 3 (normally) wins the game. The characters are also ranked in stars: Knuckles & Rouge are both 5 stars, Tikal is 4 stars, while Chaos 0 is 3 stars.

Attacks
In 2-player mode, each character is given 3 attacks that they can use, depending on how many rings you have collected.
Attack #1: 20, 80, 140, etc.
Attack #2: 40, 100, 160, etc.
Attack #3: 60, 120, 180, etc.

Knuckles & Rouge have the same attacks as in Sonic Adventure 2.
Tikal
Attack #1: Wrath of Gaia
Attack #2: Heaven's Justice
Attack #3: Captive Light
Chaos 0
Attack #1: Chaos Impact
Attack #2: Chaos Strike
Attack #3: Chaos Bind (Chaos 0's flash lasts 30 seconds while the others only last 10 seconds)

Extra Stuff

When you beat all the missions, you get another kart that you can race with Knuckles in. When you get all A's, Knuckles gets a new outfit in 2P-mode. It's different from the SA2 outfit and it allows Knuckles to use "Thunder Arrow" every 20 rings.

SCREENS

Credit for these screenshots go to Sonic Team, Gaming Age, & Gamespot.