It's not an interview. It's a recruitment drive. Even if they "hire" you...and they likely will (unless you crash the sim), you must still complete the screening and testing in China. The vast majority don't get past it.
Medical is an issue. You must be in very good health. Overweight can cause a few issues with the medical. You can still pass overweight as long as you are in good health overall. It's a very thorough exam.
The recruiters will attempt to size you up without telling you. They often reject people for silly idiosyncrasies that just rub them wrong. They are very superstitious also. Do some research on Chinese culture.
Good luck though.