After the roof was scraped off, many cracks appeared in the new house. Is it serious? How to deal with it?

As you can see, this kind of crack belongs to the shrinkage crack after concrete pouring, which has little influence on the structure. Before decoration, you can buy joint repair glue to repair and scrape joints, or 1:2 cement mortar mixed with a certain proportion of building glue. Fix it, or scrape it flat. When handling, please ask qualified decoration team personnel to handle it. I hope my answer is helpful to you.