* Best to build these 5 types of towers: Wealth, Splash Slow, Big Splash,
  Splash Poison, Pure Thunder.
* The towers mentioned above will be sufficient to deal balance damage 
  to all types of high level monsters.
* Money Steal Tower special effect does not compensate its upgrade cost.
  Wealth Tower > Money Steal.
* Other towers with special effects will be less helpful at higher level
  where monsters have 3-4 immunities.