Like the game, A small suggestion. I think you should increase the rate at which the fortify amount increases with each investment. If you have even the slightest amount of offense then by the time enemies even start to hit you their damage vastly outpaces the speed fortify can increase your HP by, even with a major investment. Basically it just scales too slowly
 "The Perfect Tower"){kind=icon}
 "The King of Towers"){kind=icon}
Hi, thanks for your suggestion, it makes perfectly sense. I will increase the fortify bonus in one of the next updates. :)