I must say this is a very addictive and fun game! Great job, but after playing several hours this morning, I got this error:
Quote: "Runtime Error 118 - Array does not exist or array subscript out of bounds at line 1763"
Also, I have a few suggestions:
a) The enemy units get damaged before the weapons hit them, I would change it so that they don't get damaged until the weapons fire actually hits them.
b) At 800x600, I can't zoom out and see the entire battlefield, I'm guessing that at 1024x768 or higher you can, I think you should check the window dimensions and allow for zooming all the way out.
c) It seems that there are really only 25 waves, and that they just keep repeating the higher you go, I think you should dramatically increase the number of enemies every 25 waves. I have gone as high as wave 197 before dying.
d) I think having the option for continous waves would be nice, maybe as a seperate "game mode".
But on the whole, it is pretty darn good