last comment, change your buttons and put an invisible box around the text so that you can click *close* to the text and it will still do whatever its meant to instead of having to click exactly onto the text, i know it sounds fussy but it is a tad annoying,
also, change power-up graphics and say how many power-ups needed till next weapon upgrade, (or maybe change the them so that its money and make them buy the upgrade 3gp for next wep or 5gp to skip one wep and gp up to wep lvls or something) sorry for spamming this up with criticism after criticism, but I'm just trying to help =)
change the planet pictures, it looks kinda tacky with them on, but keep the sorta grey dust thing it looks cool and find a replacement for the planet pics.
I like it as a starting point but it does need a few more upgrades;
1) if there was a health bar, I couldn't find it
2) make boundaries; it's not to hard, just say e.g. if (this._x>0) {speed=0}
that's if your moving using a var called xspeed and so on defining your border
if you press the top part of level 7 button you die before you start, but i love these type of games, and hopefully, ill be making some too, 5/5 cos this is perhaps my favorite genre of games for some reason
for sparten buy the thing that knocks them to the ground, and when ever they get up knock em down again, this way the NEVER get a single hit on your building, spend the rest of the money on gunmen so as the keep falling and gettin up they get shot down aswell
the idea is so good, but i think it's just impossible to make a game like this and it to be fully balanced, atm I alone can take on almost any city, and i have all the money I could want, but it is still a great attempt at it 5/5