Ooh that's interesting! It must've gone over my head haha.
If you start from the beginning, head south until you enter the next part of the map, then immediately head west for a while. You should pass the skeleton that sits on the cliff above you. Shortly after that you run into two "layers" of cliffs. If you step just between them, you're able to start walk on the cliff tiles themselves. Below is a screenshot showing an example where you continue west, walking along these walls until you jump to this other part of the map and get stuck.
Hope this helps!