"An early development idea which the gears are rotating in different direction. Looks painful if you get sandwiched." - Concept of Windy Hill Zone 1.
"The concept was totally new, so we couldn’t decide the direction of the design. It was tough as we had to re-make this first stages over and over." - Concept of Windy Zone 1.
"The inner cylinder was very confusing when designing as what it was ceiling would be a ground in next second." - Concept of Windy Hill Zone 2 (3DS)/Zone 3 (Wii U).
"When you hear desert, you will imagine pyramid and oasis. It’s a stereotype, but we felt it was very understandable." - Concept of Desert Ruins Zone 1.
"We were requested a simple design, but that makes it hard to create a sense of scale, and made Sonic look small. Taking balance to achieve this was very difficult." - Concept of Desert Ruins ruins.
"When you play the game, you actually can’t see the side part of this stage, but the design is based on a hornet’s nest." - Concept of Desert Ruins Zone 2 (Wii U).
"When you design a tropical stage, you really want to take an holiday and go there. I felt this way especially when I was making this stage." - Concept of Tropical Coast Zone 1.
"You are not copying the real world, so we sometimes get lost what kind of design is the best." - Concept of wall patterns in Tropical Coast.
"It looks flat in this art, but it is actually on a huge sphere, so it was very difficult to design." - Concept of Tropical Coast Zone 1.
"Very early image of the Casino stage. There are too many blue color and may be hard to find Sonic." - Concept of Frozen Factory Zone 3.
"There are various types of plants and trees, we re-designed many times and it was very tough to make it look “Jungle”." - Concept of Silent Forest Zone 1.
"It may be hard to recognize, but we thought it’s funny if water was coming out from the eyes and nose of Moai in the background, so we did that." - Concept of Silent Forest Zone 3.
"Did Eggman run out of budget in the final stage? You can see many patches and looks very easy to tear down this place." - Concept of Lava Mountain.