How to beat level 6-5 Omega in Super Meat Boy?

I've got up to level 6-5 Omega in Super Meat Boy. I've tried beating it dozens times now, but I fail at the same place. And my fingers hurt. :)

How can I safely go down after I get the key in this level?

I can "easily" play the level up to that key, and then I die when trying to go down. I don't even know what challenges await me after I get the key.

It is possible to simply drop from the Key's platform back to the ground below, avoiding the walls entirely. It is also possible (and perhaps intended) to simply wall hop between the two walls(though if you haven't been playing the dark world levels, you may not have had as much practice with the precise timing).

Here's a video displaying a successful run of Omega -- and remember to not give up! Getting to the key is the hard part!