2 options:

• You could treat it as a 3D game with a fixed orthographic camera. Then you could use any standard 3D games resources / books / tutorials / libraries.

• You could treat it as a top-down 2D game, with an added height property. For example, imagine a 2D grid where each tile has a height value. When moving from one tile to another, you only let a character pass to a particular tile if the characters feet are above of equal to the height of that tile, but if they are jumping and gravity brings them down on top of a tile, you let them remain there. With a bit more work you could make it so you can walk under bridges etc.

2 options:

• You could treat it as a 3D game with a fixed orthographic camera. Then you could use any standard 3D games resources / books / tutorials / libraries. Even if it rendered in 2D with sprites, the maths for movement etc would still be 3D behind the scene. This would give you the most accurate results.

• You could treat it as a top-down 2D game, with an added height property. For example, imagine a 2D grid where each tile has a height value. When moving from one tile to another, you only let a character pass to a particular tile if the character's feet are above or equal to the height of that tile, but if they are jumping and gravity brings them down on top of a tile, you let them remain there. With a bit more work you could make it so you can walk under bridges etc.