I have been thinking that finally, after living here for only 32 years, to fix up my cast basement walls. Both the inner and outer walls have been cast and the finish is not so good. You can clearly see the different widths of the boards used in the form and it hasn't been vibrated so well either. I'm not quite sure how to approach this, but I thought I would first apply some plaster that I try to get fairly smooth, and then smooth it completely with housefix so that it looks nice to paint. What do you think about this? Note that I plan to do the job myself and I'm not a plaster guru on concrete plastering 
Buy Serpo 135 and get yourself a solid Stålskånska, and you can skim coat the walls. Apply mortar on the skånska, place it at the bottom of the wall and drag it upwards while smoothing the plaster. It's not difficult even for a beginner. I did it in my basement (beginner) and could paint directly afterwards. Lime paint is good to use in basements so that moisture can migrate.