Diamond City (course)
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Despite that E. Gadd does not appear in the Diamond City-based WarioWare games, his logo can be seen in the background of the course, which appears to house Gadd Science, Incorporated. Several Magic Paintbrushes, one of E. Gadd's inventions, are also on display on this course. A statue of him is also shown in the beginning of the course.
Most of the track's buildings and structures are named after the Super Star powerup, such as the "Star Cafe", and the "Star Mart".
There are also a bunch of references to the Diamond TV company, as seen in places like the Mario Kart banner, or a business van.
Towards the end of the course at the big downhill, to the left is a building advertising for "Diamond City Taxi" and has a logo that could possibly be a reference to Sega's series: Crazy Taxi. There is also a parking lot next to the building filled with a bunch of taxis.
The race starts off on a main road that goes uphill while curving slightly to the left, and then curving slightly to the right while going back downhill. Next, the road continues straight for a while, along with the first set of Item Boxes.
Then, the road curves sharply left while going uphill and entering a futuristic factory-like structure with E. Gadd's logo all over it. The floor as well as the walls and ceiling are a bright blue color. Next, the road stops curving but still continues uphill while the racers exit the current section of the factory, as they now ride on a grey bridge with orange and purple fences leading to the next section of the factory, while still continuing uphill.
The racers then enter the next section of the factory. The road finally stops going uphill after the bridge ends. The walls are now orange and purple like the fences on the bridge, and there are yellow and purple arrows on the ceiling. There are also sections of the ceiling that hang down reading the text "Wario Kart" in bright pink text, the background is a bright yellow. The road still keeps it's grey color from the bridge, but in the middle of the road there is a pattern of bright pink and yellow squares for a short time.
After the pink and yellow squares, the whole road turns into dark orange and light orange stripes for a short time. Also, off to the sides of the road, it shows several inventions that Wario has made in the past from the WarioWare series.
Next, the road returns to its grey color and sharply curves to the right, going massively downhill. The main road from the beginning returns as the racers exit the factory. After the huge downhill, there is the second set of Item Boxes. Then, the road curves slightly to the right, goes straight for a bit, and then curves majorly to the right while going downhill.
Finally, when the road stops curving and going downhill, it continues straight for a little bit until the finish line for the next three laps.