You should concider:
1)Making the towers sellable.
2)Give the towers an upgrade function.
3)Allow a new wave to appear when you press "GO" even though the previous wave is still alive.
4)Some sort of option menu, for muting and changing in quality.
5) find some better music
How to get machinegun sniperrifle:
equip chainsaw and fire it, in the meantime you press space a couple of times so that it switches weapons, then you will equip your rifle with the chainsaw ammonition = machinegun sniperrifle :)
 "Mastermind: World Conquerer"){kind=icon}
 "Take Something Literally"){kind=icon}
 "LUV Tank"){kind=icon}
 "Frontline Defence Beta demo"){kind=icon}
 "The Last Stand"){kind=icon}
 "The Codex of Alchemical Engineering"){kind=icon}
 "Kongai"){kind=icon}