Known bugs:
Towers sometimes don't visibly fire (possibly due to firing only taking one frame)
Sometimes tower not selected when clicking too fast
Improvements to do:
Display when not enough money for purchase
Earthquakes redraw map
More towers (atleast 3, hopefully 6+)
Weapons activated by clicking (atleast 3, not including default)
Upgrades (both in game and after game)
Upgrades after game are saved to text file (.lpu)
Scoreboard that saves to a text file (.lps)
Multiple enemy types including bosses