Beginners level: 4 secs
Intermediate: 34 secs
Expert: 64 secs
I am not so proud of my current scores :(
Anyway, how the game goes depend on the number that appears. For instance, if there is 1, this means that there is one Mine that touches that number and if there is 4, it means that the No.4 touches 4 mines and that No. 4 will not touch more than 4 mines. This means that numbers that appear can share the mines or whatever it is.
The Red Flag indicated where Mines are or I believe where they are. Right clicking on the button will let you mark this Red Flag.
This pic shows when you clicked on the wrong button. I did this on purpose so as to show you all *wink*.