Enter two player mode, and select one of the inaccessible garages. Quit two player mode, and start a one player race without selecting another car to use one of the previously locked cars.
Race against Hannya
Win the all three courses in championship mode. Hannya may now be selected as an opponent in challenge mode.
Race with Hannya car
Defeat Hannya on all three courses. Dues may now be selected as an opponent in challenge mode.
Match race mode
Finish in first place under each difficulty level in championship mode.
Race with Dues car and reversed tracks
Defeat Dues on all three courses. The mirror version of all three tracks may now be selected.
Display best time
Press R at the title screen to display the time trial score for the Mountain course.
Hold Accelerate when the timer at the beginning of the race reaches "1".
Downtown track shortcut
Race past the windmills and uphill zig-zags to approach the ? mark. Locate the wide turn that is near a waterfall. Look for a tree next to a "One Way" sign near the right edge of the track. Drive towards the tree to find a gap in the fence that leads to a dirt road. Follow the road to pass through the waterfall, into a watery tunnel that will bring your car close to the finish line.