In theory, it is possible to make a top-down view platformer (like “Sonic 3D blast” and the Mario RPGs) in GDevelop, But it’s hard and time consuming, even for just a demo.
It would be a lot easier if there was a “jump” event for the top-down movement objects and some kind of (real) Z-axis.
edit: I may add that it would be a killer feature, as most of the other engines don’t have it.
edit2: they should also include a “surface+stairs” behavior in which you can edit the position in the Z-axis, and to which side the surface is leaning if it’s meant to be a stairway like in the video.
edit3: It would look like something like this:
edit4: Here’s how it’s done in GameMaker studio:
but it’s too complicated IMO, it would be an advantage to GDevelop to have a Z-axis.
edit5 A trello card have been added for this feature (2.5D platformer engine),if you’re interested, up-vote it here: Trello