The interview had a long process from HR meeting, project work (it was quite heavy since they sent a package of data for analyzing and writing a long report during 72 hr), project presentation, and CEO meeting. It took around 1 month.
However, I did not get the offer since my proposed salary did not fit with them. I have a strong background in biomedical/bioinformatics field in the EU, and coming back to HCM city is my relocation. The funniest thing was that they did not respond to anything after getting my expected salary in silence :) The starting interview process was nice and formal, but the ending was unprofessional.
In addition, they do not have a clear format for OT. I think that people need to be concerned about this point. It seems that employees will often have to work OT because clients are located in the EU/USA, and work OT without extra payment.