A job I've been putting off

The room we call the Rabbit Room - previous incumbents kept rabbits here as evidenced by the material on the floor - is the last awful floor in the house and repairing it is something I've been putting off. The boards are rubbish, the beams looks iffy and there is a 10 cm difference between the top and bottom of the floor.
Today however Sam and I started and this blip was after we had cleared out the rubbish we had stored here. The only thing left you can see is a laser spirit level that gave me the 10 cm statistic above.
It also needs rewiring, repointing and insulating as well as rebuilding the steps that give access to it so won't be a short job. I can understand why I've been procrastinating!