Well I'll include all of the updates the game needs and all that the other people are saying. 1]The colur of the bullets of the enemy and the player should be different. 2]Once a challenge is completed, we should get another one and at the end of the mission the tree should upgrade a bit. 3]Instead of buying Gun Upgrades, there should be a shop with all the guns withs their characteristics and costs. 4]Adding a 'Description' for the challenges would be a good idea as some of the titles of the challenges are confusing. 5]It would be good if we could upgrade the turrets, buying a new one is a bit too costly.
 "Greedy Ghouls"){kind=icon}
 "Solarmax"){kind=icon}
 "Upgrade Complete 2"){kind=icon}
 "I Am An Insane Rogue AI"){kind=icon}
 "Boxhead: The Zombie Wars"){kind=icon}
 "The Tickler"){kind=icon}
 "GunBot"){kind=icon}