Will an isomeric game be a problem for byond?
The movement doesn't work any differently from a programming perspective. It's still a grid with x, y, and z coordinates. There are still 8 directions (north, east, southwest, etc.). The only difference is which direction on the screen north points (by default, it points to the upper-right), but all that is handled for you by the engine. All you really need is the pixel art drawn in a proper isometric style.