I'd say on a difficulty level, I would give this job an eight.
The "kitchen side" X-frame mechanism is hardest to get to as you are working between the kitchen counter and the pantry which is like 16 inches wide and you have all the plumbing and electrical stuff in the way (the other X-frame mechanism on the front of the room (Sofa end) is much easier).
The biggest issue I had was that the new chains did not fit without grinding the end link. Similar to what was done in the video. It is a lot of frustration to work in a tight place and then discover after hours of trial and error fitting the the new parts don't match the old parts. If I had expected the chain would not fit, I would have compared it more closely, prepared it while on the work bench, and saved a lot of frustration.
But this is a job one can do - there are no special tools needed.