Looking for advice on custom sidescroller game

I’d like to create a sidescroller but instead of the level being from left to right, the maps would involve rotating around a giant spiral staircase or a similar type of cone/cylindrical shape. Ideally there would also be a limited amount of Z-depth to the game as well as the character could move away / towards the camera based at different points in the level.

I’d like to get any advice on how to implement the above. Would it be best to use the 3rd person or sidescroller game template (or neither). And if it would be advised to use either template, what modifications would be recommended to achieve what I just described?