This game's AI is too stupid to be fun. Even on the highest level all you have to do to win is buy property from others before they can make stupid trades.
In other words, if you see two of three properties (for a monopoly) gone, trade cash for one of the properties so the AI players can't make a monopoly. They will almost always trade cash for a property. They will even sell you one of two if they own it whereas no human would split up 2/3rds of a monopoly.
Plus, they think any monopoly is better than what they have. I can constantly trade the first two properties (which are a monopoly) for any one property which will give me a monopoly. In other words, if a player has a single green and I have the other two greens, it will trade the worst monopoly and give me one of the best ones.
PASS on this game.