Tip for the "Expert 160" achievement.

Choose expert on the hex mode (maybe triangle mode works as well, have not tested this). Do not bother with classic mode.
At level start, try to clear six spaces divided over the playfield, to minimize guessing at a latter stage.
(click near the upper right corner, lower right corner, lower mid, lower left, upper left and upper mid)
If this succeeded (you did not accidently trigger a mine), you will have multiple openings from which you can progress upon.
And you will minimize the chances you have to guess, later on.

After some practice and the mandatory luck, you eventually will succeed and get under 160 seconds! Good luck!