The stocks are good... but I personally think you should make them A. Stocks should Sky rocket at times (or just steadily increase) and B. Crash. It's too easy to predict how the stocks will turn out... normally there's no need to look at the % Increase because the stocks have a min. and max. Also it would be sweet if you bought 50% or more of a stock you become the head of the board of directors
The game, is quite easy and fun :) I`m trying to get the "hard" badge :D, although it likes to taunt me sometimes when i accidentally count wrong >.> (thanks math teacher)
I`m workng on what u`ve just described. Stock simulation will be much much better with it