Have you tried any type of chemical paint stripper on the concrete walls with the plaster technique? I have used a stripper by 3-M Company with great success on many surfaces. It's non-toxic, has no odor, clings extremely well to vertical surfaces, and does a pretty great job of softening painted surfaces. You can wash the residue off with soap and warm water, and it does not need to be neutralized. Since the only thing behind your paint is a concrete wall, it's not likely that you'll damage anything by using this stripper, and it will make the removal much easier and more complete.
As for the carpeting... well, you can probably expect that it's attached with some type of product like Liquid Nails. If it's on drywall, plan for that to be ruined, so new drywall is probably in your future.
Also, once you remove the carpet, the Disco Ball in the center of the ceiling will probably also have to be replaced, as it will no longer go with the decor. (Sorry, I couldn't resist!)