I can't believe I didn't post this months ago but everyone should do this regardless of how fast your computer is because Joymax coded this feature completely wrong in my opinion (though it's more like horrendously inefficient than wrong)
On the in game menu click options and on the video tab change shadows to none.
On a lagging scale of 1 to 10 with 1 being smooth as butter and 10 being a slideshow, Detailed shadows is an 11, Circle shadows is a 3 and Nothing is a 1.
I can turn everything to the minimum and turn circle shadows on and it lags more than with everything maxed out and circle shadows off. Unfortunately, the default when you install the game is Circle if I remember correctly so turn it off and it will help immensely
