Hmmm..Help perhaps?
Making a balance is everything you need to ensure fair game play!!
Players like me has a hard time trying to earn enough upkeep to continue buying towers or upgrades....While the resources (gold pieces) and tower (kept getting shoot easily) is depleting seriously, the enemies got so seriously strong, that it makes them quite hard to defeat with the towers we have....
See the significant inverse gradient behind it?? You got to try harder on it....
Otherwise, the graphics are quite well-made, and i love the gameplay up till 7/10 and 4/5!!!