Good but one breaking point

While the game is over all good it has one game breaking feature. The amount you get per kill does not increase. I cant find a way to get an increase. This makes upgrading and buying towers to a level needed impossible. There are items to destroy for money but once they are gone you have nothing. A piggy bank that you have to upgrade (which cost money) is very limited help. By the time it maxes out you dont need it. It takes 20+ levels to max the bank at tier one. And cost 400 to upgrade it. That is over 30 kills. Oh and kills are a flat rate of $12. Lowest tower is $100.
Either scale the reward with the difficulty of the creeps or remain a broken game.
Update: the last level is impossible. At level 45 and 20 normal creeps and 4 bosses. Wish I could give negative stars.

Deathrite about The Creeps!, v1.15.17