NA Release: Feb 7, 2006 (Nov 17 on PC)
JP Release: Feb 23, 2006
EU Release: Mar 13, 2006 (Nov 24 on PC)

STORY MODE

As this game is a racing game, most levels are a race with seven characters against you. You have no choice in which character to use for each stage as that has been pre-determined. There is the Hero Story, Babylon Story, and the "unlocked" stages for each story. There are cutscenes that tell you what is going on just before a particular race. Knuckles has only one stage in story mode and that's Egg Factory. Egg Factory is the third stage for the Heroes. To beat the stage, Knuckles must come in first place. Prior to the stage, Knuckles and Storm have a "I'm better than you"-conversation that reflects in part on Knuckles punching Storm off his gear in the opening of the Hero Story.

RACE MODE

The tracks available to be used will depend on what has been unlocked due to the other modes in the game.
Free Race: Compete against one other person and/or the computer. In the rules, you can set the total laps (1-99), turn announcements on/off, turn leveling up on/off, turn items on/off, turn air pits on/off, and set whether the race ends or you run when running out of air.
Time Attack: Complete the track as fast as possible. In the rules, you can turn announcements on/off and decide whether a prior saved "ghost" will race with you.
World Grand Prix: Compete against one other person and/or the computer on 5 different tracks (based on Hero/Babylon stories). You earn points based on how well you finish in each race. Depending on how many points you earn, you will get a ring bonus at the end, which is useful for buying gear at the shop. In the rules, you can turn announcements on/off, turn leveling up on/off, turn items on/off, turn air pits on/off, and set whether the race ends or you run when running out of air.

TAG MODE

In this mode, you and one other person/computer will race against another duo. You both need to stay relatively close to each other or else the one that is in front will be "shocked" and unable to move until the other gets in range. Whichever team has one of its members cross the finish line first wins. In the rules, you can set the total laps (1-99) and turn air pits on/off.

SURVIVAL MODE

Race: You can compete against one other person and/or the computer. You need to get and keep the chaos emerald while going through scattered gates within a time limit to score points before any of the other racers do it. In the rules, you can turn items on/off, set the time limit (1-99), and set the number of points (1-99).
Battle: Compete against one other persond and/or the computer in fights until one racer remains. This mode has different courses from the rest of the game. The courses here are Dual Towers, Snow Valley, and Space Theater. Throughout each course, there are special items that can increase your attack or defense. In the rules, you can turn turn items on/off and set the time limit (1-99).

MISSION MODE

This mode is unlocked after defeating story mode. More information will be added later.

KNUCKLES' GEAR

Knuckles' special extreme gear is called "Red Rock." Below are the other extreme gears that Knuckles can use in the game. New gear can be purchased in the shop based on the number of rings you have collected by the end of each race. The rings accumulate so you do not need to collect the required amount in one race--which for some gear would be impossible anyway due to the amount rings available in a race and how many rings are needed for some of the more special gears. The stats when viewing the Gear Gallery are shown below. If the stat differs from what is shown for when Knuckles uses the gear (based on Normal Race Mode), that number is in parentheses. The information below is based on what True Red has purchased/unlocked. More will be added later.

#3 Red Rock

By Robotnik Corp. Power-type air-board.
Dash: 3
Limit: 4 (3)
Power: 3 (4)
Cornering: 2

#10 High Booster

Astounding boost ability.
Dash: 2
Limit: 3 (2)
Power: 2 (3)
Cornering: 2

#11 Auto Slider

Auto air slides when cornering.
Dash: 3
Limit: 3 (2)
Power: 3 (4)
Cornering: 2

#18 Beginner

Consumes little air. Good for beginners.
Dash: 2
Limit: 3 (2)
Power: 2 (3)
Cornering: 1

#19 Accelerator

By Robotnik Corp. Speed boost enhanced.
Dash: 5
Limit: 2 (1)
Power: 2 (3)
Cornering: 2

#26 Hovercraft

Gear said to be used on a grand adventure.
Dash: 4
Limit: 6 (5)
Power: 4 (5)
Cornering: 3

#28 Faster

By Robotnik Corp. Top speed enhanced.
Dash: 1
Limit: 6 (5)
Power: 3 (4)
Cornering: 1

#30 Power Gear

By Robotnik Corp. Endurance enhanced.
Dash: 2
Limit: 4 (3)
Power: 5 (6)
Cornering: 2

ITEMS

Air: Tops off your air tank by various amounts
Explosion: Causes a bomb to roll and attack racers in front
High Speed: Boosts your speed for a limited time
Invincible Barrier: Protection from all attacks/obstacles (except falling off the track) for a limited time
Magnetic Barrier: Attracts all rings to you for a limited time
Question: Any random item
Rings: Allows for leveling up after a certain amount has been collected during a race; also used to buy new gear at the shop
Speed Down: Slows you down dramatically for a limited time

SCREENS

Credit for these screenshots go to Sega (America/Japan) and Kikizo.