Spiral Tower, as it's name states, is mainly a large spiraling tower that always goes upwards.
White Bomberman must make it to the exit near the top. Earning the target score involves climbing a bit higher from the exit. After making it to the exit, the next level, Snake Route, is unlocked.
There is an Adok Bomb present in this level. White Bomberman must climb higher from the exit and he can get it on a ledge.