Hi,
Medical check is quite thorough. If there is anything wrong with you, they will find out. They won't fail you for stuff like high cholesterol or being overweight as long as everything else is ok.
Your agency should provide you with feedback questions for the Air Law exam. They should also send you the Korean AIP for reference so if you have the time, you should look at this too. There are a lot of questions about penalties and fines. It seems when something goes wrong, a fine will fix everything!!
Sim check, I can't comment on what they are looking for from 330 guys but it will be pretty straight forward with the usual engine failures etc.
Hope this helps