Use a mushroom on the first boost ramp to skip the middle platform.
Super Mario Kart
Bowser Castle 1 appeared in the first Mario Kart games. This takes place just inside the Bowser's castle. There is lava and savage Thwomps that are all over the race track. There are mud-puddles that can slow you down. But you can see there are few zippers and boosters that will speed you up.
Mario Kart: Super Circuit
Bowser Castle 1 also appeared in third Mario Kart games and series. It has own Bowser Castle 1 for nitro, but it also uses SMK's Bowser Castle 1 for retro. It shows horrible 2D fuzzy look, but in Mario Kart 7, it shows really good 3D graphic look.
Mario Kart 7
Bowser Castle also appeared as a second track of Shell Cup. There are no modifications, but there is a brand new gliding pad near the pool of mud, pool of magma with boosters showing fire-scheme color. Coins also appeared in this game and this game shows enhanced 3D graphic look.